Tag Archives: Coral

High marine extinction risk by 2100

If marine extinction is not a reality for many species by the end of this century, scientists say, it will certainly be a strong probability.

LONDON, 9 October, 2017 – Mass marine extinction may be inevitable. If humans go on burning fossil fuels under the notorious “business as usual” scenario, then by 2100 they will have added so much carbon to the world’s oceans that a sixth mass extinction of marine species will follow, inexorably.

And even if the 197 nations that agreed in Paris in 2015 to take steps to limit global warming in fact do so, then by 2100 humans will have added 300 billion tons of carbon to the seas. And a US scientist has calculated that the critical threshold for mass extinction stands at 310 billion tons.

So in either case, the world will be condemned to, or at imminent risk of, a “great dying” of the kind that characterised the end of the geological period called the Permian, in which 95% of marine species vanished, or the Cretaceous era that witnessed the last of the dinosaurs.

Daniel Rothman, a geophysicist at the Massachusetts Institute of Technology, reports in the journal Science Advances that he worked through hundreds of scientific studies to identify 31 occasions of significant change in 542 million years in the planet’s carbon cycle – in which plants draw down carbon from the atmosphere and cycle it through the animal community and back into the atmosphere.

Happening now

For each event, including the five great mass extinctions in the geological record, he estimated the record of carbon preserved in the rocks, to find a predictable threshold at which catastrophe might be an outcome. Four of the five great extinction events lay beyond this threshold. He then considered the timescales of such extinction events to arrive at his modern-day danger zone figure of 310 billion tons.

And by 2100, unconstrained fossil fuel combustion may have tipped the planet into “unknown territory,” he says.

“This is not saying that disaster occurs the next day. It’s saying that, if left unchecked, the carbon cycle would move into a realm which would no longer be stable, and would behave in a way that would be difficult to predict. In the geologic past, this type of behaviour is associated with mass extinction.”

In effect, Professor Rothman has used a mathematical technique to predict an event many biologists believe is already happening. Pollution, the clearing of the wilderness and the disruption of habitat have already placed many species at risk. Global warming as a consequence of the combustion of fossil fuels will, they have repeatedly said, make a bad situation worse.

“Our activities as humans are pushing species to the brink so fast that it’s impossible for conservationists to assess the declines in real time. Even those species that we thought were abundant and safe now face an imminent threat of extinction”

Researchers have already begun to record local extinctions – the disappearance of once-familiar creatures from local landscapes – and climate change that will follow global warming could heighten the hazard for animals and plants already under stress.

And Professor Rothman’s warning came hard on the heels of several studies that indicate the dangerous impact of climate change.

Scientists from the University of Washington in Seattle warn that as the world’s waters warm, fish will have to migrate to surviveand those that cannot – the ones in lakes and river systems – could be at risk.

They report in the journal Nature Climate Change that they looked at available physiological data and climate predictions to see how 3,000 species in oceans and rivers would respond to warmer waters and to judge what the “breaking point” temperatures for any species would be.

Many losers

“Nowhere on Earth are fish spared from having to cope with climate change”, said senior author Julian Olden, professor of aquatic and fishery sciences. “Fish have unique challenges – they either have to make rapid movements to track their temperature requirements, or they will be forced to adapt quickly.”

But other creatures in the most extreme environments are affected too. British Antarctic Survey scientists report in Nature Climate Change that they used computer models to test a warming scenario for 900 species of marine invertebrates that live in the south polar seas.

Even a small warming of 0.4°C will cause unique local animals to change their distribution, and although some will fare well, overall there will be more losers than winners.

“While a few species might thrive at least during the early decades of warming, the future for a whole range of invertebrates from starfish to corals is bleak, and there’s nowhere to swim to, nowhere to hide when you’re sitting on the bottom of the world’s coldest and most southerly ocean and it’s getting warmer by the decade”, said Huw Griffiths, the Survey scientist who led the research.

Africa in jeopardy

As if to hammer home the message, the International Union for the Conservation of Nature has just issued its latest warnings on imminent extinction. This international body has now rated 25,062 species as in danger of extinction out of a list of more than 87,000.

The latest list includes five of the six species of ash tree native to North America, some of them threatened by an invasive beetle infestation, helped by global warming, and five species of African antelope.

“Our activities as humans are pushing species to the brink so fast that it’s impossible for conservationists to assess the declines in real time,” says Inger Andersen, director general of the IUCN.

“Even those species that we thought were abundant and safe – such as antelopes in Africa or ash trees in the US – now face an imminent threat of extinction.” – Climate News Network

If marine extinction is not a reality for many species by the end of this century, scientists say, it will certainly be a strong probability.

LONDON, 9 October, 2017 – Mass marine extinction may be inevitable. If humans go on burning fossil fuels under the notorious “business as usual” scenario, then by 2100 they will have added so much carbon to the world’s oceans that a sixth mass extinction of marine species will follow, inexorably.

And even if the 197 nations that agreed in Paris in 2015 to take steps to limit global warming in fact do so, then by 2100 humans will have added 300 billion tons of carbon to the seas. And a US scientist has calculated that the critical threshold for mass extinction stands at 310 billion tons.

So in either case, the world will be condemned to, or at imminent risk of, a “great dying” of the kind that characterised the end of the geological period called the Permian, in which 95% of marine species vanished, or the Cretaceous era that witnessed the last of the dinosaurs.

Daniel Rothman, a geophysicist at the Massachusetts Institute of Technology, reports in the journal Science Advances that he worked through hundreds of scientific studies to identify 31 occasions of significant change in 542 million years in the planet’s carbon cycle – in which plants draw down carbon from the atmosphere and cycle it through the animal community and back into the atmosphere.

Happening now

For each event, including the five great mass extinctions in the geological record, he estimated the record of carbon preserved in the rocks, to find a predictable threshold at which catastrophe might be an outcome. Four of the five great extinction events lay beyond this threshold. He then considered the timescales of such extinction events to arrive at his modern-day danger zone figure of 310 billion tons.

And by 2100, unconstrained fossil fuel combustion may have tipped the planet into “unknown territory,” he says.

“This is not saying that disaster occurs the next day. It’s saying that, if left unchecked, the carbon cycle would move into a realm which would no longer be stable, and would behave in a way that would be difficult to predict. In the geologic past, this type of behaviour is associated with mass extinction.”

In effect, Professor Rothman has used a mathematical technique to predict an event many biologists believe is already happening. Pollution, the clearing of the wilderness and the disruption of habitat have already placed many species at risk. Global warming as a consequence of the combustion of fossil fuels will, they have repeatedly said, make a bad situation worse.

“Our activities as humans are pushing species to the brink so fast that it’s impossible for conservationists to assess the declines in real time. Even those species that we thought were abundant and safe now face an imminent threat of extinction”

Researchers have already begun to record local extinctions – the disappearance of once-familiar creatures from local landscapes – and climate change that will follow global warming could heighten the hazard for animals and plants already under stress.

And Professor Rothman’s warning came hard on the heels of several studies that indicate the dangerous impact of climate change.

Scientists from the University of Washington in Seattle warn that as the world’s waters warm, fish will have to migrate to surviveand those that cannot – the ones in lakes and river systems – could be at risk.

They report in the journal Nature Climate Change that they looked at available physiological data and climate predictions to see how 3,000 species in oceans and rivers would respond to warmer waters and to judge what the “breaking point” temperatures for any species would be.

Many losers

“Nowhere on Earth are fish spared from having to cope with climate change”, said senior author Julian Olden, professor of aquatic and fishery sciences. “Fish have unique challenges – they either have to make rapid movements to track their temperature requirements, or they will be forced to adapt quickly.”

But other creatures in the most extreme environments are affected too. British Antarctic Survey scientists report in Nature Climate Change that they used computer models to test a warming scenario for 900 species of marine invertebrates that live in the south polar seas.

Even a small warming of 0.4°C will cause unique local animals to change their distribution, and although some will fare well, overall there will be more losers than winners.

“While a few species might thrive at least during the early decades of warming, the future for a whole range of invertebrates from starfish to corals is bleak, and there’s nowhere to swim to, nowhere to hide when you’re sitting on the bottom of the world’s coldest and most southerly ocean and it’s getting warmer by the decade”, said Huw Griffiths, the Survey scientist who led the research.

Africa in jeopardy

As if to hammer home the message, the International Union for the Conservation of Nature has just issued its latest warnings on imminent extinction. This international body has now rated 25,062 species as in danger of extinction out of a list of more than 87,000.

The latest list includes five of the six species of ash tree native to North America, some of them threatened by an invasive beetle infestation, helped by global warming, and five species of African antelope.

“Our activities as humans are pushing species to the brink so fast that it’s impossible for conservationists to assess the declines in real time,” says Inger Andersen, director general of the IUCN.

“Even those species that we thought were abundant and safe – such as antelopes in Africa or ash trees in the US – now face an imminent threat of extinction.” – Climate News Network

Marine reserves protect against warming climate

Marine reserves can give protection against the impacts of climate change to both sea life and land-dwelling species, including humans.

LONDON, 7 June, 2017 – Protecting more of the world’s seas offers a double benefit, scientists say. Marine reserves protect fish and other sea creatures against exploitation and pollution. They can also help life both in the oceans and on land to cope with the growing impacts of a warmer climate.

Matt Rand, director of the Pew Bertarelli Ocean Legacy project, which supported part of the research, said: “Marine reserves are climate reserves.” 

An international study has found that reserves help marine ecosystems and people adapt to five harmful consequences of climate change: ocean acidification; sea-level rise; the increased intensity of storms; shifts in species distribution, and decreased productivity and availability of oxygen.

Reserves also can also help to increase the long-term storage of carbon from greenhouse gas emissions, especially in coastal wetlands, which helps to reduce the rate of climate change, the study found.

Published in the Proceedings of the National Academy of Sciences, it evaluated existing peer reviewed studies on the impact of marine reserves around the world.

Climate lens

The lead author, Professor Callum Roberts of the University of York, UK, said: “Many studies show that well-managed marine reserves can protect wildlife and support productive fisheries, but we wanted to explore this body of research through the lens of climate change to see whether these benefits could help ameliorate or slow its impacts.

“It was soon quite clear that they can offer the ocean ecosystem and people critical resilience benefits to rapid climate change.”

Only 3.5 % of the world’s oceans has so far been set aside for protection, with just 1.6 % given full protection from exploitation. International groups are working to raise the total to 10% by 2020.

Delegates to the International Union for the Conservation of Nature’s 2016 World Conservation Congress agreed that at least 30% of the oceans should be protected by 2030.

Stock recovery 

Scientists say marine reserves and marine protected areas (MPAs) protect coasts from sea-level rise and can help to sustain coastal wetlands, mudflats and coral reefs that can act to absorb the impact of storms and extreme weather.

They also help to offset declines in ocean and fisheries productivity caused by climate change, for example through the growing acidification of seawater and the reduction in plankton abundance.  

The reserves protect key coastal systems – mangroves, salt marshes and seagrasses – creating localised reductions in carbon dioxide concentrations and water acidity. And they can provide refuges for fish as they adjust their ranges to changing conditions. 

Previously published research revealed that marine reserves can promote the rapid recovery of exploited species and damaged habitats while safeguarding intact ecosystems. With fishing outlawed and other human activity limited, they can create very productive areas which allow exploited stocks and degraded habitats to recover.

“This study should be proof positive to decision makers that creating effectively managed marine reserves can deliver a multitude of benefits”

These benefits are greater in large, long-established, well-managed reserves that have full protection from activities such as fishing and oil and mineral extraction. Relative isolation from damaging human activities adds further conservation benefits.

The research shows that protecting more of the ocean will also improve the outlook for environmental recovery after greenhouse gas emissions have been brought under control.

It reinforces the IUCN’s argument that the UN ocean protection target should be raised from 10% to 30% of the oceans, which will require many more large-scale MPAs and protected areas beyond national jurisdiction.

Beth O’Leary, a co-author and a research fellow at the University of York, said: “We were keenly aware that marine reserves can increase species’ abundance and help alleviate food scarcity, but our evaluation showed reserves are a viable low-tech, cost-effective adaptation strategy.”

Matt Rand of Ocean Legacy said: “This study should be proof positive to decision makers that creating effectively managed marine reserves can deliver a multitude of benefits.” – Climate News Network 

Marine reserves can give protection against the impacts of climate change to both sea life and land-dwelling species, including humans.

LONDON, 7 June, 2017 – Protecting more of the world’s seas offers a double benefit, scientists say. Marine reserves protect fish and other sea creatures against exploitation and pollution. They can also help life both in the oceans and on land to cope with the growing impacts of a warmer climate.

Matt Rand, director of the Pew Bertarelli Ocean Legacy project, which supported part of the research, said: “Marine reserves are climate reserves.” 

An international study has found that reserves help marine ecosystems and people adapt to five harmful consequences of climate change: ocean acidification; sea-level rise; the increased intensity of storms; shifts in species distribution, and decreased productivity and availability of oxygen.

Reserves also can also help to increase the long-term storage of carbon from greenhouse gas emissions, especially in coastal wetlands, which helps to reduce the rate of climate change, the study found.

Published in the Proceedings of the National Academy of Sciences, it evaluated existing peer reviewed studies on the impact of marine reserves around the world.

Climate lens

The lead author, Professor Callum Roberts of the University of York, UK, said: “Many studies show that well-managed marine reserves can protect wildlife and support productive fisheries, but we wanted to explore this body of research through the lens of climate change to see whether these benefits could help ameliorate or slow its impacts.

“It was soon quite clear that they can offer the ocean ecosystem and people critical resilience benefits to rapid climate change.”

Only 3.5 % of the world’s oceans has so far been set aside for protection, with just 1.6 % given full protection from exploitation. International groups are working to raise the total to 10% by 2020.

Delegates to the International Union for the Conservation of Nature’s 2016 World Conservation Congress agreed that at least 30% of the oceans should be protected by 2030.

Stock recovery 

Scientists say marine reserves and marine protected areas (MPAs) protect coasts from sea-level rise and can help to sustain coastal wetlands, mudflats and coral reefs that can act to absorb the impact of storms and extreme weather.

They also help to offset declines in ocean and fisheries productivity caused by climate change, for example through the growing acidification of seawater and the reduction in plankton abundance.  

The reserves protect key coastal systems – mangroves, salt marshes and seagrasses – creating localised reductions in carbon dioxide concentrations and water acidity. And they can provide refuges for fish as they adjust their ranges to changing conditions. 

Previously published research revealed that marine reserves can promote the rapid recovery of exploited species and damaged habitats while safeguarding intact ecosystems. With fishing outlawed and other human activity limited, they can create very productive areas which allow exploited stocks and degraded habitats to recover.

“This study should be proof positive to decision makers that creating effectively managed marine reserves can deliver a multitude of benefits”

These benefits are greater in large, long-established, well-managed reserves that have full protection from activities such as fishing and oil and mineral extraction. Relative isolation from damaging human activities adds further conservation benefits.

The research shows that protecting more of the ocean will also improve the outlook for environmental recovery after greenhouse gas emissions have been brought under control.

It reinforces the IUCN’s argument that the UN ocean protection target should be raised from 10% to 30% of the oceans, which will require many more large-scale MPAs and protected areas beyond national jurisdiction.

Beth O’Leary, a co-author and a research fellow at the University of York, said: “We were keenly aware that marine reserves can increase species’ abundance and help alleviate food scarcity, but our evaluation showed reserves are a viable low-tech, cost-effective adaptation strategy.”

Matt Rand of Ocean Legacy said: “This study should be proof positive to decision makers that creating effectively managed marine reserves can deliver a multitude of benefits.” – Climate News Network 

Sea floor erosion causes coral reefs to sink

Coral reefs Molokini crater near Maui

Five US coral reefs are sinking beneath the waves due to the erosion of the sea floor, robbing coastal communities of their natural storm barrier.

LONDON, 28 April, 2017 – The world’s coral reefs are not just in hot water and under threat from acid attack; they may even be getting out of their depth. New research around five US coral reefs shows that even as sea levels rise, the sea floor around the reefs is being eroded.

And coral growth simply may not be fast enough to keep up, which means that coastal communities in Florida, the Caribbean and Hawaii could become increasingly at risk from storms, waves and erosion.

The news comes close after revelations that great tracts of Australia’s Great Barrier Reef, like other coral colonies, have been devastated by bleaching, as ocean temperatures rise above the levels that corals – animals that live in symbiosis with algae – can tolerate, and researchers have warned that this could soon be happening to reefs almost everywhere, every year.

Coral under threat

There is already widespread alarm among marine scientists as the seas become measurably more acidic due to an increase in levels of carbon dioxide in the atmosphere, and this too poses a threat to corals everywhere.

But while researchers in the tropics had monitored the living reefs of the surface waters, hardly anybody had paid attention to the sea floor around the reefs.

Now, scientists of the US Geological Survey report in Biogeosciences that – possibly as a consequence of the degradation of the reefs of the Florida Keys, the US Virgin Islands and the Hawaiian island of Maui – the sea floor is being scoured of sand and sediments, just as sea levels continue to creep to a predicted rise of up to a metre by 2100.

Around Maui, they report, they measured the loss enough sand, rock and shell to fill the Empire State Building in New York 81 times over.

At current rates, by 2100 sea floor erosion could
increase water depths by two to eight times more than
what has been predicted from sea level rise alone”

This means that the seas along those coasts have become unexpectedly deep. Since tropical corals depend for nourishment on light photosynthesised by their algal partners at the surface, this raises yet another hazard: if the sea floor is falling at the same time as the seawater ceiling is going up, can corals grow fast enough to keep up?

Our measurements show that seafloor erosion has already caused water depths to increase to levels not predicted to occur until near the year 2100,” says Kimberly Yates, a biogeochemist at the USGS’s St Petersburg Coastal and Marine Science Centre, who led the research.

At current rates, by 2100 sea floor erosion could increase water depths by two to eight times more than what has been predicted from sea level rise alone.”

Healthy coral reefs are among the richest and most diverse habitats on the planet. They represent an immediate asset to human communities: they underwrite tourism and fisheries, and they deliver protection against storm surge and tsunami for around 200 million people in low-lying coastal communities.

Sea level rise presents a threat to communities along the coasts of all the inhabited continents, and coastal flooding could by 2100 be costing the world $100 trillion a year.

One group has calculated that money spent on protecting and restoring reefs would represent a bargain, at about one-twentieth the cost of artificial breakwaters.

Reefs in decline

The USGS team identify no specific cause for erosion around the reefs, but they point out that reefs worldwide are in decline because of coastal development, pollution, coral bleaching, disease and acidification.

They worked from seafloor measurements taken by the US government’s own National Oceanic and Atmospheric Administration between 1934 and 1982, and more recent surveys by the US Army Corps of Engineers and LIDAR data gathered by remote sensing. Across all five sites they examined, they found that the sea floor had become lower, in some cases by as much as 0.8 metres.

We saw lower rates of erosion – and even some localised increases in seafloor elevation – in areas that were protected, near refuges or distant from human population centres,” Dr Yates says. “But these were not significant enough to offset the ecosystem-wide pattern of erosion at each of our study sites.”
Climate News Network

Five US coral reefs are sinking beneath the waves due to the erosion of the sea floor, robbing coastal communities of their natural storm barrier.

LONDON, 28 April, 2017 – The world’s coral reefs are not just in hot water and under threat from acid attack; they may even be getting out of their depth. New research around five US coral reefs shows that even as sea levels rise, the sea floor around the reefs is being eroded.

And coral growth simply may not be fast enough to keep up, which means that coastal communities in Florida, the Caribbean and Hawaii could become increasingly at risk from storms, waves and erosion.

The news comes close after revelations that great tracts of Australia’s Great Barrier Reef, like other coral colonies, have been devastated by bleaching, as ocean temperatures rise above the levels that corals – animals that live in symbiosis with algae – can tolerate, and researchers have warned that this could soon be happening to reefs almost everywhere, every year.

Coral under threat

There is already widespread alarm among marine scientists as the seas become measurably more acidic due to an increase in levels of carbon dioxide in the atmosphere, and this too poses a threat to corals everywhere.

But while researchers in the tropics had monitored the living reefs of the surface waters, hardly anybody had paid attention to the sea floor around the reefs.

Now, scientists of the US Geological Survey report in Biogeosciences that – possibly as a consequence of the degradation of the reefs of the Florida Keys, the US Virgin Islands and the Hawaiian island of Maui – the sea floor is being scoured of sand and sediments, just as sea levels continue to creep to a predicted rise of up to a metre by 2100.

Around Maui, they report, they measured the loss enough sand, rock and shell to fill the Empire State Building in New York 81 times over.

At current rates, by 2100 sea floor erosion could
increase water depths by two to eight times more than
what has been predicted from sea level rise alone”

This means that the seas along those coasts have become unexpectedly deep. Since tropical corals depend for nourishment on light photosynthesised by their algal partners at the surface, this raises yet another hazard: if the sea floor is falling at the same time as the seawater ceiling is going up, can corals grow fast enough to keep up?

Our measurements show that seafloor erosion has already caused water depths to increase to levels not predicted to occur until near the year 2100,” says Kimberly Yates, a biogeochemist at the USGS’s St Petersburg Coastal and Marine Science Centre, who led the research.

At current rates, by 2100 sea floor erosion could increase water depths by two to eight times more than what has been predicted from sea level rise alone.”

Healthy coral reefs are among the richest and most diverse habitats on the planet. They represent an immediate asset to human communities: they underwrite tourism and fisheries, and they deliver protection against storm surge and tsunami for around 200 million people in low-lying coastal communities.

Sea level rise presents a threat to communities along the coasts of all the inhabited continents, and coastal flooding could by 2100 be costing the world $100 trillion a year.

One group has calculated that money spent on protecting and restoring reefs would represent a bargain, at about one-twentieth the cost of artificial breakwaters.

Reefs in decline

The USGS team identify no specific cause for erosion around the reefs, but they point out that reefs worldwide are in decline because of coastal development, pollution, coral bleaching, disease and acidification.

They worked from seafloor measurements taken by the US government’s own National Oceanic and Atmospheric Administration between 1934 and 1982, and more recent surveys by the US Army Corps of Engineers and LIDAR data gathered by remote sensing. Across all five sites they examined, they found that the sea floor had become lower, in some cases by as much as 0.8 metres.

We saw lower rates of erosion – and even some localised increases in seafloor elevation – in areas that were protected, near refuges or distant from human population centres,” Dr Yates says. “But these were not significant enough to offset the ecosystem-wide pattern of erosion at each of our study sites.”
Climate News Network

World’s reefs damaged beyond repair

reefs great barrier reef

Australia’s Great Barrier Reef and reefs in the Maldives have been dangerously weakened by coral bleaching caused by global warming and El Niño events.

LONDON, 24 March, 2017 The Great Barrier Reef, one of the wonders of the Pacific Ocean, may never fully recover from the combined effects of global warming and an El Niño year, according to a new study in one of the world’s leading science journals.

And a second study, in a second journal, warns that increased sea surface temperatures have also caused both a major die-off of corals and the collapse of reef growth rates in the Maldives, in the Indian Ocean.

Corals are very sensitive to ocean temperatures, and in unusually hot years and these have recurred naturally and cyclically since long before humans started burning coal, oil and gas, to accelerate the build-up of greenhouse gases in the atmosphere – the corals react to stress by bleaching. That is, they eject the photosynthesising algae that live with them in symbiosis, to the advantage of both creatures.

Hotter oceans

But the world’s oceans are becoming hotter anyway, because of global warming driven by greenhouse gas concentrations in the atmosphere. The seas are becoming ever more acidic as atmospheric carbon dioxide reacts with the water.

And the periodic return of a blister of oceanic heat in the eastern Pacific called El Niño – Spanish for “The Child”, because it becomes most visible around Christmastime – has begun to put the world’s reefs at risk. The El Niño of 2015-16 triggered a massive episode of bleaching throughout the tropics. And, Australian researchers say in Nature, the bleaching continues.

We’re hoping that the next two to three weeks will cool off quickly, and this year’s bleaching won’t be anything like last year. The severity of the 2016 bleaching was off the chart,” says Terry Hughes, of Australia’s Centre of Excellence for Coral Reef Studies, at James Cook University in Queensland.

It was the third major bleaching to affect the Great Barrier Reef, following earlier heatwaves in 1998 and 2002. Now we’re gearing up to study a potential number four.

We have now assessed whether past exposure to bleaching in 1998 and 2002 made reefs any more tolerant in 2016. Sadly, we found no evidence that past bleaching makes the corals any tougher.”

Recovery from similar past disturbances
in the Maldives has taken 10-15 years, but major
bleaching events are predicted to become
far more frequent than this”

Researchers have already warned that, unless there is urgent action to limit global warming by drastically reducing dependence on fossil fuel as an energy source, severe bleaching could damage 99% of the world’s coral reefs.

The reefs are among the richest ecosystems on the planet, and they provide vital coastal protection for human settlements as well as a source of sustainable protein for human economies.

It broke my heart to see so many corals dying on northern reefs on the Great Barrier Reef in 2016,” says Professor Hughes. “With rising temperatures due to global warming, it’s only a matter of time before we see more of these events. A fourth event after only one year is a major blow to the Reef.”

British scientists saw much the same devastation from the same El Niño bleaching around the Maldives in the Indian Ocean, they write in Scientific Reports journal. And the big question now is: how quickly can the Indian Ocean reefs recover?

Growth rate of reefs

Recovery from similar past disturbances in the Maldives has taken 10-15 years, but major bleaching events are predicted to become far more frequent than this. If this is the case it could lead to long-term loss of reef growth and so limit the coastal protection and habitat services these reefs presently provide,” says Chris Perry, professor of physical geography at the University of Exeter, UK.

The most alarming aspect of this coral die-off event is that it has led to a rapid and very large decline in the growth rate of the reefs.

This in turn has major implications not only for the capacity of these reefs to match any increases in sea-level, but because it is also likely to lead to a loss of the surface structure of the reefs that is so critical for supporting fish species diversity and abundance.” Climate News Network

Australia’s Great Barrier Reef and reefs in the Maldives have been dangerously weakened by coral bleaching caused by global warming and El Niño events.

LONDON, 24 March, 2017 The Great Barrier Reef, one of the wonders of the Pacific Ocean, may never fully recover from the combined effects of global warming and an El Niño year, according to a new study in one of the world’s leading science journals.

And a second study, in a second journal, warns that increased sea surface temperatures have also caused both a major die-off of corals and the collapse of reef growth rates in the Maldives, in the Indian Ocean.

Corals are very sensitive to ocean temperatures, and in unusually hot years and these have recurred naturally and cyclically since long before humans started burning coal, oil and gas, to accelerate the build-up of greenhouse gases in the atmosphere – the corals react to stress by bleaching. That is, they eject the photosynthesising algae that live with them in symbiosis, to the advantage of both creatures.

Hotter oceans

But the world’s oceans are becoming hotter anyway, because of global warming driven by greenhouse gas concentrations in the atmosphere. The seas are becoming ever more acidic as atmospheric carbon dioxide reacts with the water.

And the periodic return of a blister of oceanic heat in the eastern Pacific called El Niño – Spanish for “The Child”, because it becomes most visible around Christmastime – has begun to put the world’s reefs at risk. The El Niño of 2015-16 triggered a massive episode of bleaching throughout the tropics. And, Australian researchers say in Nature, the bleaching continues.

We’re hoping that the next two to three weeks will cool off quickly, and this year’s bleaching won’t be anything like last year. The severity of the 2016 bleaching was off the chart,” says Terry Hughes, of Australia’s Centre of Excellence for Coral Reef Studies, at James Cook University in Queensland.

It was the third major bleaching to affect the Great Barrier Reef, following earlier heatwaves in 1998 and 2002. Now we’re gearing up to study a potential number four.

We have now assessed whether past exposure to bleaching in 1998 and 2002 made reefs any more tolerant in 2016. Sadly, we found no evidence that past bleaching makes the corals any tougher.”

Recovery from similar past disturbances
in the Maldives has taken 10-15 years, but major
bleaching events are predicted to become
far more frequent than this”

Researchers have already warned that, unless there is urgent action to limit global warming by drastically reducing dependence on fossil fuel as an energy source, severe bleaching could damage 99% of the world’s coral reefs.

The reefs are among the richest ecosystems on the planet, and they provide vital coastal protection for human settlements as well as a source of sustainable protein for human economies.

It broke my heart to see so many corals dying on northern reefs on the Great Barrier Reef in 2016,” says Professor Hughes. “With rising temperatures due to global warming, it’s only a matter of time before we see more of these events. A fourth event after only one year is a major blow to the Reef.”

British scientists saw much the same devastation from the same El Niño bleaching around the Maldives in the Indian Ocean, they write in Scientific Reports journal. And the big question now is: how quickly can the Indian Ocean reefs recover?

Growth rate of reefs

Recovery from similar past disturbances in the Maldives has taken 10-15 years, but major bleaching events are predicted to become far more frequent than this. If this is the case it could lead to long-term loss of reef growth and so limit the coastal protection and habitat services these reefs presently provide,” says Chris Perry, professor of physical geography at the University of Exeter, UK.

The most alarming aspect of this coral die-off event is that it has led to a rapid and very large decline in the growth rate of the reefs.

This in turn has major implications not only for the capacity of these reefs to match any increases in sea-level, but because it is also likely to lead to a loss of the surface structure of the reefs that is so critical for supporting fish species diversity and abundance.” Climate News Network

Coral bleaching could spark annual reef havoc

Before 2100, almost every reef in the world will suffer severe coral bleaching annually unless fossil fuel consumption is sharply reduced.

LONDON, 14 January, 2017 – Some time this century, if humans go on burning fossil fuels at the present rate, severe bleaching will hit 99% of coral reefs every year. Coral bleaching happens when the organisms become uncomfortably hot, and reject the algae on which their lives ultimately depend.

Since it takes a reef five years to recover from any one bleaching event, the consequences for some of the world’s richest ecosystems could be catastrophic. But catastrophe could be delayed. Drastic cuts in emissions reductions could give reefs an average of another 11 years before they start bleaching every year, according to new research.

Right now, the world’s reefs are caught up in the longest global coral bleaching event ever recorded. It began in 2014, and could go on well into 2017, according to the journal Scientific Reports

Corals are acutely sensitive to ocean temperatures and when the thermometer rises, their symbiotic relationship with a mutual beneficiary, the zooxanthellae, breaks down. Some 90% of the Great Barrier Reef off Australia has been affected by the latest episode, and 20% of the coral killed.

“Bleaching that takes place every year will invariably cause major changes in the ecological function of coral reef ecosystems,” said Ruben van Hooidonk of the US National Oceanic and Atmospheric Administration and the University of Miami.

“Further, annual bleaching will greatly reduce the capacity of coral reefs to provide goods and services, such as fisheries and coastal protection, to human communities.”

Acid trend

The warning supports earlier studies that have already predicted problems for the world’s reefs by the century’s end. The reefs are being hit by changes in ocean chemistry, as carbon dioxide levels rise and as waters become more acidic

Changing conditions make reefs vulnerable to new predators. And biologists have warned, again and again, that reefs are home to around a quarter of all marine life, and worth an estimated $375bn a year to humans, as coastal protection, as fishery nurseries, and as a source of tourism.

And even if corals recover from bleaching, and pollution, they could still be vulnerable to drowning as sea levels rise. A new study in the journal Global and Planetary Change has identified a crisis at the Great Barrier Reef 125,000 years ago, when polar ice melted, sea levels rose by perhaps six metres, and the reef’s corals all but perished.

“The findings highlight the importance of increasing the reef’s resilience now,” said Belinda Dechnik of the University of Sydney, who led the research..

“In combination with climate change predictions by the Intergovernmental Panel on Climate Change and in the absence of improvements to reef management and human impacts, sea level pressures could tip the reef over the edge, potentially drowning it for good.”

But the latest computer model predictions revealed in Scientific Reports deliver even more urgency, more global detail and more alarm. There are 87 countries or territories that are home to 500 square kilometres or more of reef .

“ . . . annual bleaching will greatly reduce the capacity of coral reefs to provide goods and services, such as fisheries and coastal protection”

On average, these reefs will start to experience annual bleaching by 2043. This will leave the living corals vulnerable to starvation and disease.

About one reef system in twenty will already be hotter and have started bleaching a decade before that. Among the first will be reefs around Taiwan and the Turks and Caicos Islands. 

Some 11% of reefs will be affected a decade later than average, and these include the corals off Bahrain, Chile and French Polynesia.

If nations adhere to an international agreement made in Paris in December 2015 to limit global warming to 1.5°C, the annual bleaching experience could be delayed by another 11 years.

The low latitude reefs of the South Pacific, India, Florida and the Great Barrier off Australia could be protected for another 25 years. In effect, the research has identified the conservation priorities.

“These predictions are a treasure trove for those who are fighting to protect one of the world’s most magnificent and important ecosystems from the ravages of climate change,” said Erik Solheim, head of the UN Environment Programme.

“It is imperative that we take these predictions seriously and that, at the very minimum, we meet the targets of the Paris Agreement. Doing so will buy time for coral reefs and allow us to plan for the future and adapt to the present.” – Climate News Network

Before 2100, almost every reef in the world will suffer severe coral bleaching annually unless fossil fuel consumption is sharply reduced.

LONDON, 14 January, 2017 – Some time this century, if humans go on burning fossil fuels at the present rate, severe bleaching will hit 99% of coral reefs every year. Coral bleaching happens when the organisms become uncomfortably hot, and reject the algae on which their lives ultimately depend.

Since it takes a reef five years to recover from any one bleaching event, the consequences for some of the world’s richest ecosystems could be catastrophic. But catastrophe could be delayed. Drastic cuts in emissions reductions could give reefs an average of another 11 years before they start bleaching every year, according to new research.

Right now, the world’s reefs are caught up in the longest global coral bleaching event ever recorded. It began in 2014, and could go on well into 2017, according to the journal Scientific Reports

Corals are acutely sensitive to ocean temperatures and when the thermometer rises, their symbiotic relationship with a mutual beneficiary, the zooxanthellae, breaks down. Some 90% of the Great Barrier Reef off Australia has been affected by the latest episode, and 20% of the coral killed.

“Bleaching that takes place every year will invariably cause major changes in the ecological function of coral reef ecosystems,” said Ruben van Hooidonk of the US National Oceanic and Atmospheric Administration and the University of Miami.

“Further, annual bleaching will greatly reduce the capacity of coral reefs to provide goods and services, such as fisheries and coastal protection, to human communities.”

Acid trend

The warning supports earlier studies that have already predicted problems for the world’s reefs by the century’s end. The reefs are being hit by changes in ocean chemistry, as carbon dioxide levels rise and as waters become more acidic

Changing conditions make reefs vulnerable to new predators. And biologists have warned, again and again, that reefs are home to around a quarter of all marine life, and worth an estimated $375bn a year to humans, as coastal protection, as fishery nurseries, and as a source of tourism.

And even if corals recover from bleaching, and pollution, they could still be vulnerable to drowning as sea levels rise. A new study in the journal Global and Planetary Change has identified a crisis at the Great Barrier Reef 125,000 years ago, when polar ice melted, sea levels rose by perhaps six metres, and the reef’s corals all but perished.

“The findings highlight the importance of increasing the reef’s resilience now,” said Belinda Dechnik of the University of Sydney, who led the research..

“In combination with climate change predictions by the Intergovernmental Panel on Climate Change and in the absence of improvements to reef management and human impacts, sea level pressures could tip the reef over the edge, potentially drowning it for good.”

But the latest computer model predictions revealed in Scientific Reports deliver even more urgency, more global detail and more alarm. There are 87 countries or territories that are home to 500 square kilometres or more of reef .

“ . . . annual bleaching will greatly reduce the capacity of coral reefs to provide goods and services, such as fisheries and coastal protection”

On average, these reefs will start to experience annual bleaching by 2043. This will leave the living corals vulnerable to starvation and disease.

About one reef system in twenty will already be hotter and have started bleaching a decade before that. Among the first will be reefs around Taiwan and the Turks and Caicos Islands. 

Some 11% of reefs will be affected a decade later than average, and these include the corals off Bahrain, Chile and French Polynesia.

If nations adhere to an international agreement made in Paris in December 2015 to limit global warming to 1.5°C, the annual bleaching experience could be delayed by another 11 years.

The low latitude reefs of the South Pacific, India, Florida and the Great Barrier off Australia could be protected for another 25 years. In effect, the research has identified the conservation priorities.

“These predictions are a treasure trove for those who are fighting to protect one of the world’s most magnificent and important ecosystems from the ravages of climate change,” said Erik Solheim, head of the UN Environment Programme.

“It is imperative that we take these predictions seriously and that, at the very minimum, we meet the targets of the Paris Agreement. Doing so will buy time for coral reefs and allow us to plan for the future and adapt to the present.” – Climate News Network

Humans sparked warming nearly 200 years ago

Human activity prompted an early start to global warming, scientists say – nearly 200 years ago, long before previous studies had suggested.

LONDON, 30 August, 2016 – Global warming may have started far earlier than anyone has so far imagined. The first signs of climate change driven by rising levels of atmospheric carbon dioxide may have been there in the year the world’s first intercity railway link opened between Manchester and Liverpool, when the Duke of Wellington was still Prime Minister of Britain, when an angry Parisian mob overturned the French monarchy in 1830.

But if so – and climate scientists and modellers will argue whether in fact humans sparked warming so early – the evidence is available only with benefit of a long time series and twenty-twenty hindsight.

Nerilie Abramclimate scientist at the Australian National University, and international colleagues in the Past Global Changes consortium known as PAGES report in the journal Nature that they looked once again at all the climate data – records and proxy evidence from ice cores and ocean sediments – since 1500 AD.

What they saw there was that the sustained trend of warming in the 20th century may have shown its first signs in the tropical oceans and over some parts of the land surfaces of the Northern Hemisphere as early as the 1830s.

Before the first novels of Charles Dickens, before Queen Victoria, there may have been the first signs of anthropogenic warming. This is earlier than anybody expected, including the scientists who have just published the research.

Surprise

“It was an extraordinary finding,” said Dr Abram. “It was one of those moments where science really surprised us. But the results were clear. What we are witnessing today started about 180 years ago.”

Corals, like trees, have annual growth rings, and these too can tell a story of climate change. By bringing together coral measurements and evidence from sea floor sediments, the scientists recorded a steady turn for the warmer in ocean temperatures early in the 19th century.

“Somebody living in the 1830s or even the 1890s would not have been able to distinguish that there was this change afoot,” she said. “It’s by having this long record now that extends almost 200 years from that point that we can go back and say ‘Well, this was when the changes first started.’”

The observation had to be backed up by computer simulation: the very early 19th century had been marked by catastrophic volcanic eruptions, one of which – Mount Tambora in Indonesia in 1815 – led to the notorious “Year without a Summer”.

That followed in 1816, when the poets Byron, Shelley and  Mary Shelley and young Dr Polidori shivered away in a villa in Geneva, and left the world the legacy of Frankenstein and the first vampire novel.

“In some ways it is really a positive message, because it suggests that the climate system can respond very quickly to relatively small changes in greenhouse gases”

Theoretically, the warming could have been a response to the recovery after the eruptions. But, said Nicholas McKay, a climate scientist at Northern Arizona University, and one of the authors, this is not the case.

”If you run the models with only volcanoes and no increase in greenhouse gases, you see a warming, starting in the early 1800s. But then it levels off, and you don’t see that warming continue through the 20th century,” he said.

But once the increases in greenhouse gases were incorporated, the globe started warming around 1830 and carried on warming, just as the coral records showed.

“In some ways it is really a positive message, because it suggests that the climate system can respond very quickly to relatively small changes in greenhouse gases,” he said.

“It means that our actions as a society, both positive and negative, can result in an immediate impact.” – Climate News Network

Human activity prompted an early start to global warming, scientists say – nearly 200 years ago, long before previous studies had suggested.

LONDON, 30 August, 2016 – Global warming may have started far earlier than anyone has so far imagined. The first signs of climate change driven by rising levels of atmospheric carbon dioxide may have been there in the year the world’s first intercity railway link opened between Manchester and Liverpool, when the Duke of Wellington was still Prime Minister of Britain, when an angry Parisian mob overturned the French monarchy in 1830.

But if so – and climate scientists and modellers will argue whether in fact humans sparked warming so early – the evidence is available only with benefit of a long time series and twenty-twenty hindsight.

Nerilie Abramclimate scientist at the Australian National University, and international colleagues in the Past Global Changes consortium known as PAGES report in the journal Nature that they looked once again at all the climate data – records and proxy evidence from ice cores and ocean sediments – since 1500 AD.

What they saw there was that the sustained trend of warming in the 20th century may have shown its first signs in the tropical oceans and over some parts of the land surfaces of the Northern Hemisphere as early as the 1830s.

Before the first novels of Charles Dickens, before Queen Victoria, there may have been the first signs of anthropogenic warming. This is earlier than anybody expected, including the scientists who have just published the research.

Surprise

“It was an extraordinary finding,” said Dr Abram. “It was one of those moments where science really surprised us. But the results were clear. What we are witnessing today started about 180 years ago.”

Corals, like trees, have annual growth rings, and these too can tell a story of climate change. By bringing together coral measurements and evidence from sea floor sediments, the scientists recorded a steady turn for the warmer in ocean temperatures early in the 19th century.

“Somebody living in the 1830s or even the 1890s would not have been able to distinguish that there was this change afoot,” she said. “It’s by having this long record now that extends almost 200 years from that point that we can go back and say ‘Well, this was when the changes first started.’”

The observation had to be backed up by computer simulation: the very early 19th century had been marked by catastrophic volcanic eruptions, one of which – Mount Tambora in Indonesia in 1815 – led to the notorious “Year without a Summer”.

That followed in 1816, when the poets Byron, Shelley and  Mary Shelley and young Dr Polidori shivered away in a villa in Geneva, and left the world the legacy of Frankenstein and the first vampire novel.

“In some ways it is really a positive message, because it suggests that the climate system can respond very quickly to relatively small changes in greenhouse gases”

Theoretically, the warming could have been a response to the recovery after the eruptions. But, said Nicholas McKay, a climate scientist at Northern Arizona University, and one of the authors, this is not the case.

”If you run the models with only volcanoes and no increase in greenhouse gases, you see a warming, starting in the early 1800s. But then it levels off, and you don’t see that warming continue through the 20th century,” he said.

But once the increases in greenhouse gases were incorporated, the globe started warming around 1830 and carried on warming, just as the coral records showed.

“In some ways it is really a positive message, because it suggests that the climate system can respond very quickly to relatively small changes in greenhouse gases,” he said.

“It means that our actions as a society, both positive and negative, can result in an immediate impact.” – Climate News Network

Coral reefs die as El Niño hots up

The third mass coral bleaching in recent history is under way, as record ocean warmth creates a crisis in the tropics.

LONDON, 11 October, 2015 – Record sea temperatures combined with a strong El Niño are causing widespread coral bleaching, which is threatening to kill over 12,000 square kilometres of reefs.

The US National Oceanic and Atmospheric Administration (NOAA) has declared a global bleaching event, making this only the third such crisis in recorded history.

NOAA’s declaration has implications for the livelihoods of 500 million people worldwide and income worth $30 billion, because reefs support 25% of all marine species and are a nursery ground for many species of fish.

The bleaching is directly connected to climate change: it is the warmer water that causes the problem. The first global bleaching event was in 1998 and the second in 2010, both in years marked by El Niños, the periodic climate phenomenon in the Pacific. 

Each time the potential for damage has been greater because the sea has been warmer before the start of the El Niño. This August the ocean was the warmest on record – and this time NOAA’s estimate is that 38% of the world’s reefs may be affected.

Huge losses

Coral bleaching this year began in the Florida Keys and South Florida in August. Record bleaching is now taking place in Hawaii; it is spreading to the Caribbean and may last until the New Year.

As the exceptionally warm water spreads across the Pacific the bleaching event is expected to hit the Great Barrier Reef in Australia in early 2016, causing more damage, some of it permanent.

Mark Eakin, NOAA’s Coral Reef Watch coordinator, said: “The coral bleaching and disease brought on by climate change, and coupled with events like the current El Niño, are the largest and most pervasive threats to coral reefs around the world.

“As a result, we are losing huge areas of coral across the US, as well as internationally. What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it’s likely to last well into 2016.”

Corals live in symbiosis with algae, and the two creatures depend on each other for survival. The apparent bleaching happens because as sea temperatures rise above coral comfort levels, the increasingly stressed corals and the colourful algae part company. 

Protection lost

As a result, the corals whiten, lose their source of nutrients and – if the bleaching goes on for too long – will die.

Minor bleaching can be repaired and reefs recover, but at high temperatures and on this scale large areas can die. Apart from the loss of the corals, damage to the tourist industry and fishing, it also increases flood risk, because healthy reefs act as a storm barrier for many islands and low-lying coasts.

Graphic illustrations of bleaching can be seen on a website set up to alert people to the dangers and record the event. 

There is particular concern on Hawaii at the moment. It suffered bad bleaching in 2014, which is currently getting worse.

Record warming

Eakin said the bleaching was a crisis. “Hawaii is getting hit with the worst coral bleaching they have ever seen, right now. It’s severe. It’s extensive. And it’s on all the islands.

“In one part of northwestern Hawaii the reef just completely bleached and all of the coral is dead and covered with scuzzy algae.”

The bleaching has also struck Cuba, Haiti and the Dominican Republic and is about to hit Puerto Rico and the Virgin Islands, he said. Oceans worldwide are by far the warmest on record – August 2015 was two-fifths of a degree warmer than August 1998. Eakin said: “Next year may be as bad as this year or even worse.”

Gregor Hodgson, who heads the group Reef Check Australia, is concerned about the forecast that the warm blob of water caused by El Niño will hit the country’s Great Barrier Reef early next year.

The reef is the planet’s biggest, a world heritage site and a magnet for tourists. The computer model forecasts “this horrendous, dramatic” impact on the reef, Hodgson said. “It’s truly terrifying.” – Climate News Network

The third mass coral bleaching in recent history is under way, as record ocean warmth creates a crisis in the tropics.

LONDON, 11 October, 2015 – Record sea temperatures combined with a strong El Niño are causing widespread coral bleaching, which is threatening to kill over 12,000 square kilometres of reefs.

The US National Oceanic and Atmospheric Administration (NOAA) has declared a global bleaching event, making this only the third such crisis in recorded history.

NOAA’s declaration has implications for the livelihoods of 500 million people worldwide and income worth $30 billion, because reefs support 25% of all marine species and are a nursery ground for many species of fish.

The bleaching is directly connected to climate change: it is the warmer water that causes the problem. The first global bleaching event was in 1998 and the second in 2010, both in years marked by El Niños, the periodic climate phenomenon in the Pacific. 

Each time the potential for damage has been greater because the sea has been warmer before the start of the El Niño. This August the ocean was the warmest on record – and this time NOAA’s estimate is that 38% of the world’s reefs may be affected.

Huge losses

Coral bleaching this year began in the Florida Keys and South Florida in August. Record bleaching is now taking place in Hawaii; it is spreading to the Caribbean and may last until the New Year.

As the exceptionally warm water spreads across the Pacific the bleaching event is expected to hit the Great Barrier Reef in Australia in early 2016, causing more damage, some of it permanent.

Mark Eakin, NOAA’s Coral Reef Watch coordinator, said: “The coral bleaching and disease brought on by climate change, and coupled with events like the current El Niño, are the largest and most pervasive threats to coral reefs around the world.

“As a result, we are losing huge areas of coral across the US, as well as internationally. What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it’s likely to last well into 2016.”

Corals live in symbiosis with algae, and the two creatures depend on each other for survival. The apparent bleaching happens because as sea temperatures rise above coral comfort levels, the increasingly stressed corals and the colourful algae part company. 

Protection lost

As a result, the corals whiten, lose their source of nutrients and – if the bleaching goes on for too long – will die.

Minor bleaching can be repaired and reefs recover, but at high temperatures and on this scale large areas can die. Apart from the loss of the corals, damage to the tourist industry and fishing, it also increases flood risk, because healthy reefs act as a storm barrier for many islands and low-lying coasts.

Graphic illustrations of bleaching can be seen on a website set up to alert people to the dangers and record the event. 

There is particular concern on Hawaii at the moment. It suffered bad bleaching in 2014, which is currently getting worse.

Record warming

Eakin said the bleaching was a crisis. “Hawaii is getting hit with the worst coral bleaching they have ever seen, right now. It’s severe. It’s extensive. And it’s on all the islands.

“In one part of northwestern Hawaii the reef just completely bleached and all of the coral is dead and covered with scuzzy algae.”

The bleaching has also struck Cuba, Haiti and the Dominican Republic and is about to hit Puerto Rico and the Virgin Islands, he said. Oceans worldwide are by far the warmest on record – August 2015 was two-fifths of a degree warmer than August 1998. Eakin said: “Next year may be as bad as this year or even worse.”

Gregor Hodgson, who heads the group Reef Check Australia, is concerned about the forecast that the warm blob of water caused by El Niño will hit the country’s Great Barrier Reef early next year.

The reef is the planet’s biggest, a world heritage site and a magnet for tourists. The computer model forecasts “this horrendous, dramatic” impact on the reef, Hodgson said. “It’s truly terrifying.” – Climate News Network

Global warming means double jeopardy for sea life

Some sea creatures seeking to escape warming oceans as the mercury rises will find that climate change is damaging the areas which could give them refuge. LONDON, 9 June, 2015 − Global warming is likely to drive marine creatures away from the equator in search of new and cooler habitats − and  is likely to limit the safest options for many migrant fish, crabs and corals. One problem for marine life is that warmer waters hold less oxygen, so the corals that move to higher latitudes will have to settle in shallower water to take advantage of the diminishing light. This, too, creates hazards. Curtis Deutsch, an oceanographer at the University of Washington in the US, and colleagues report in the journal Science that the ocean’s denizens could be heading for respiratory stress. Warmer waters speed up the metabolic need for oxygen, but those same warmer waters hold lower levels of dissolved gases. “If your metabolism goes up, you need more food and you need more oxygen,” Dr Deutsch says. “This means that aquatic animals could become oxygen-starved in the warmer future, even if oxygen doesn’t change. We know that oxygen levels in the ocean are going down now, and will decrease more with climate warming.”

Shifting habitats

His co-author, Hans-Otto Pörtner, head of the Department of Integrative Ecophysiology at the Alfred Wegener Institute in Bremerhaven, Germany, says: “If the oxygen level in a given region of the ocean drops below a species’ minimum requirements, it forces the animals to abandon their native habitat. This combines with the effect of warmer temperatures. “Since animals evade to cooler regions, their habitat shifts towards the poles or to greater water depths. In Atlantic cod and many other fish species, we can already observe the shift now.” That change is undoubtedly on the way. One group has just calculated that between 50% and 70% of the world’s oceans could see changes in biodiversity as the sea surface temperatures creep upwards. The next question is: what kinds of change and what kinds of habitat will be available for submarine climate refugees? The researchers chose four well-studied marine species for their simulations of the impact of climate change on the maritime world.

Combined stress

These are the open ocean-dweller Atlantic cod, the coastal water-dwelling Atlantic rock crab, the sharp snout sea bream of the sub-tropical Atlantic and Mediterranean, and the common eelpout, a bottom-dwelling fish that lives in the shallow waters of the high northern latitudes. The study suggests that, for many species, the combined stress of higher metabolic rates and lower levels of dissolved oxygen will mean that possible habitats will contract by between 14% and 26% because at the present species’ ranges nearer the equator, peak oxygen demand would become greater than the supply. Also in Science journal, a team led by Paul Muir, acting curator for corals at the Museum of Tropical Queensland in Australia, reports on the potential future for 104 species of staghorn corals – the tiny creatures whose skeletons make up the reefs that offer the richest habitats in the tropical seas. Corals are sensitive to extremes of temperature. As the mercury levels climb, they can “bleach” and reject the algae on which they depend for survival. And if conditions are too hot for too long, they can perish.

Little sunlight

But the Australian team found that these animals, too, are caught in a kind of habitat trap. As they migrate away from the equator, they must nest in shallower water to take advantage of the lower levels of winter sunlight that penetrate the waters at higher latitudes. The corals are likely to have to rise 0.6 metres for every one degree of latitude of migration. But there is a limit to how high in the water they can rise because, at a certain point, temperature, salinity and wave damage will start to take their toll. “The two studies remind us that climate change will reshape marine species’ habitats, but not necessarily expand them,” warns Joan Kleypas, a marine ecologist/geologist at the US National Centre for Atmospheric Research, in the same journal. “Both studies highlight little-recognised barriers to future range expansions in the oceans,” he says. “Each is based on physiological limitations of marine organisms that are quantifiable, and thus increase our ability to predict species habitats into the future.” − Climate News Network

Some sea creatures seeking to escape warming oceans as the mercury rises will find that climate change is damaging the areas which could give them refuge. LONDON, 9 June, 2015 − Global warming is likely to drive marine creatures away from the equator in search of new and cooler habitats − and  is likely to limit the safest options for many migrant fish, crabs and corals. One problem for marine life is that warmer waters hold less oxygen, so the corals that move to higher latitudes will have to settle in shallower water to take advantage of the diminishing light. This, too, creates hazards. Curtis Deutsch, an oceanographer at the University of Washington in the US, and colleagues report in the journal Science that the ocean’s denizens could be heading for respiratory stress. Warmer waters speed up the metabolic need for oxygen, but those same warmer waters hold lower levels of dissolved gases. “If your metabolism goes up, you need more food and you need more oxygen,” Dr Deutsch says. “This means that aquatic animals could become oxygen-starved in the warmer future, even if oxygen doesn’t change. We know that oxygen levels in the ocean are going down now, and will decrease more with climate warming.”

Shifting habitats

His co-author, Hans-Otto Pörtner, head of the Department of Integrative Ecophysiology at the Alfred Wegener Institute in Bremerhaven, Germany, says: “If the oxygen level in a given region of the ocean drops below a species’ minimum requirements, it forces the animals to abandon their native habitat. This combines with the effect of warmer temperatures. “Since animals evade to cooler regions, their habitat shifts towards the poles or to greater water depths. In Atlantic cod and many other fish species, we can already observe the shift now.” That change is undoubtedly on the way. One group has just calculated that between 50% and 70% of the world’s oceans could see changes in biodiversity as the sea surface temperatures creep upwards. The next question is: what kinds of change and what kinds of habitat will be available for submarine climate refugees? The researchers chose four well-studied marine species for their simulations of the impact of climate change on the maritime world.

Combined stress

These are the open ocean-dweller Atlantic cod, the coastal water-dwelling Atlantic rock crab, the sharp snout sea bream of the sub-tropical Atlantic and Mediterranean, and the common eelpout, a bottom-dwelling fish that lives in the shallow waters of the high northern latitudes. The study suggests that, for many species, the combined stress of higher metabolic rates and lower levels of dissolved oxygen will mean that possible habitats will contract by between 14% and 26% because at the present species’ ranges nearer the equator, peak oxygen demand would become greater than the supply. Also in Science journal, a team led by Paul Muir, acting curator for corals at the Museum of Tropical Queensland in Australia, reports on the potential future for 104 species of staghorn corals – the tiny creatures whose skeletons make up the reefs that offer the richest habitats in the tropical seas. Corals are sensitive to extremes of temperature. As the mercury levels climb, they can “bleach” and reject the algae on which they depend for survival. And if conditions are too hot for too long, they can perish.

Little sunlight

But the Australian team found that these animals, too, are caught in a kind of habitat trap. As they migrate away from the equator, they must nest in shallower water to take advantage of the lower levels of winter sunlight that penetrate the waters at higher latitudes. The corals are likely to have to rise 0.6 metres for every one degree of latitude of migration. But there is a limit to how high in the water they can rise because, at a certain point, temperature, salinity and wave damage will start to take their toll. “The two studies remind us that climate change will reshape marine species’ habitats, but not necessarily expand them,” warns Joan Kleypas, a marine ecologist/geologist at the US National Centre for Atmospheric Research, in the same journal. “Both studies highlight little-recognised barriers to future range expansions in the oceans,” he says. “Each is based on physiological limitations of marine organisms that are quantifiable, and thus increase our ability to predict species habitats into the future.” − Climate News Network

Climate helps trees to wax as corals wane

Some tree species in central Europe are growing faster as the climate changes, while the rising levels of acid it causes are endangering coral in Australia’s Great Barrier Reef. LONDON, 29 September 2014 – Europe’s spruce trees have started to sprint for growth. Beech trees, too, have begun to accelerate. German scientists report that trees in the European forests have increased their growth speeds by up to 77% since 1960. The researchers can say this with confidence because in southern Germany they have access to the oldest network of measured experimental forest plots in the world. Since 1870, foresters and scientists have made 600,000 measurements of individual trees in Bavaria. Hans Pretzsch and colleagues at the Technical University of Munich report in the journal Nature Communications that they selected beech and spruce for their comparisons because these are the dominant species in the forests of Central Europe. The deciduous beech trees were growing 77% faster, and the evergreen spruce by 32% . The best explanation is that the trees are responding to rising average temperatures and a longer growing season: both consequences of climate change. It is also possible that higher atmospheric concentrations of carbon dioxide are contributing to faster growth. The research was carried out in forests that – 40 years ago – were thought to be in danger of dieback from atmospheric pollution: at the time, environmentalists were more worried about acid rain from factory and power station emissions than about global warming, and the German word Waldsterben entered the international vocabulary. “Interestingly we observed that acid rain only had a temporary slowing effect on the growth of our experimental plots. Indeed, the input of pollutants started to fall off from the 1970s,” said Professor Pretzsch.

“Coral reefs are getting hammered and are likely to become a thing of the past unless we start running our economy as if the sea and sky matters to us, very soon”

Although the trees have both grown and aged faster, the forests as a whole have not greatly changed. The expectation is that foresters will be able to take trees for timber significantly faster. But other denizens of the forests may have to learn to adapt. “The plant and animal species that will be most affected are those living in habitats which depend on special phases and structures of forest development. These species may have to become more mobile to survive.” But if global warming is good for tree growth, it still isn’t doing much for the coral reefs. US scientists at work on Australia’s Great Barrier Reef report in the journal Geochimica et Cosmochimica Acta  that coral growth rates have fallen 40% since the mid-1970s. Jacob Silverman of the Carnegie Institution and Ken Caldeira and others studied a stretch of reef where measurements were first recorded 30 years ago, and made comparisons. They found that the rates of calcification, important in shell and skeletal growth, were 40% lower in 2008 and 2009 than during the same season in 1975 and 1976. This time, the change could be put down not to warming, but to the change in water chemistry. As frequently reported by the Climate News Network, as atmospheric carbon dioxide dissolves in the oceans, it changes the pH value of the water, making it gradually more acidic, with sometimes serious consequences for some families of fish and shellfish. “Coral reefs are getting hammered,” says Professor Caldeira. “Ocean acidification, global warming, coastal pollution and overfishing are all damaging coral reefs. “Coral reefs have been around for millions of years but are likely to become a thing of the past unless we start running our economy as if the sea and sky matters to us, very soon.” – Climate News Network

Some tree species in central Europe are growing faster as the climate changes, while the rising levels of acid it causes are endangering coral in Australia’s Great Barrier Reef. LONDON, 29 September 2014 – Europe’s spruce trees have started to sprint for growth. Beech trees, too, have begun to accelerate. German scientists report that trees in the European forests have increased their growth speeds by up to 77% since 1960. The researchers can say this with confidence because in southern Germany they have access to the oldest network of measured experimental forest plots in the world. Since 1870, foresters and scientists have made 600,000 measurements of individual trees in Bavaria. Hans Pretzsch and colleagues at the Technical University of Munich report in the journal Nature Communications that they selected beech and spruce for their comparisons because these are the dominant species in the forests of Central Europe. The deciduous beech trees were growing 77% faster, and the evergreen spruce by 32% . The best explanation is that the trees are responding to rising average temperatures and a longer growing season: both consequences of climate change. It is also possible that higher atmospheric concentrations of carbon dioxide are contributing to faster growth. The research was carried out in forests that – 40 years ago – were thought to be in danger of dieback from atmospheric pollution: at the time, environmentalists were more worried about acid rain from factory and power station emissions than about global warming, and the German word Waldsterben entered the international vocabulary. “Interestingly we observed that acid rain only had a temporary slowing effect on the growth of our experimental plots. Indeed, the input of pollutants started to fall off from the 1970s,” said Professor Pretzsch.

“Coral reefs are getting hammered and are likely to become a thing of the past unless we start running our economy as if the sea and sky matters to us, very soon”

Although the trees have both grown and aged faster, the forests as a whole have not greatly changed. The expectation is that foresters will be able to take trees for timber significantly faster. But other denizens of the forests may have to learn to adapt. “The plant and animal species that will be most affected are those living in habitats which depend on special phases and structures of forest development. These species may have to become more mobile to survive.” But if global warming is good for tree growth, it still isn’t doing much for the coral reefs. US scientists at work on Australia’s Great Barrier Reef report in the journal Geochimica et Cosmochimica Acta  that coral growth rates have fallen 40% since the mid-1970s. Jacob Silverman of the Carnegie Institution and Ken Caldeira and others studied a stretch of reef where measurements were first recorded 30 years ago, and made comparisons. They found that the rates of calcification, important in shell and skeletal growth, were 40% lower in 2008 and 2009 than during the same season in 1975 and 1976. This time, the change could be put down not to warming, but to the change in water chemistry. As frequently reported by the Climate News Network, as atmospheric carbon dioxide dissolves in the oceans, it changes the pH value of the water, making it gradually more acidic, with sometimes serious consequences for some families of fish and shellfish. “Coral reefs are getting hammered,” says Professor Caldeira. “Ocean acidification, global warming, coastal pollution and overfishing are all damaging coral reefs. “Coral reefs have been around for millions of years but are likely to become a thing of the past unless we start running our economy as if the sea and sky matters to us, very soon.” – Climate News Network

Warmer Atlantic widens invader’s hunting ground

The exotic lionfish, already a long way from the reefs of its Indo-Pacific home, is heading further north up the US coast as global warming causes big changes to ocean habitats. LONDON, 28 September, 2014 − The venomous lionfish is on the move. This invasive species has been observed in deeper waters off the North Carolina coast since the turn of the century, but new research suggests it may now be expanding its range into the shallower levels. Since the lionfish (Pterois volitans) is actually native to the Indo-Pacific region, it is already a long way from home. But what now gives it licence to hunt further north is warmer sea temperature. Global warming has already begun to make huge differences to ocean habitat. The bluefin tuna is a temperate zone fish that has already been observed in Arctic waters off the coast of Greenland, and commercial species such as red mullet, a creature of the Mediterranean, has been seen in the North Sea and even in Norwegian waters. Now researchers in the US have reported that the lionfish – an invader first observed off the Florida coast in the 1980s − is spreading through the north-west Atlantic. Temperature is the key determinant for a fish on the move. Fisheries biologist Paula Whitfield, of the National Oceanic and Atmospheric Administration’s National Centres for Coastal Ocean Science, and colleagues report in the journal Marine Ecology Progress Series that they surveyed 40 species of fish off the reefs of North Carolina.

Tropical species

These reefs have always been home both to temperate and tropical species, at the limits of their ranges. But now the reefs are becoming more tropical − and so is the local population. “Along the North Carolina coast, warming water temperatures may allow the expansion of tropical fish species, such as lionfish, into areas that were previously uninhabitable due to cold winter temperatures,” Whitfield says. “The temperature thresholds collected in this study will allow us to detect and estimate fish community changes related to water temperature.” The lionfish tends to prefer water warmer than 15.2°C, and so normally inhabits the warm currents of the deeper waters in the temperate Atlantic. It is a carnivore that seems to enjoy a wide range of prey. It makes itself at home in a wide variety of habitat, and is considered a serious threat to other species of reef fish. – Climate News Network

The exotic lionfish, already a long way from the reefs of its Indo-Pacific home, is heading further north up the US coast as global warming causes big changes to ocean habitats. LONDON, 28 September, 2014 − The venomous lionfish is on the move. This invasive species has been observed in deeper waters off the North Carolina coast since the turn of the century, but new research suggests it may now be expanding its range into the shallower levels. Since the lionfish (Pterois volitans) is actually native to the Indo-Pacific region, it is already a long way from home. But what now gives it licence to hunt further north is warmer sea temperature. Global warming has already begun to make huge differences to ocean habitat. The bluefin tuna is a temperate zone fish that has already been observed in Arctic waters off the coast of Greenland, and commercial species such as red mullet, a creature of the Mediterranean, has been seen in the North Sea and even in Norwegian waters. Now researchers in the US have reported that the lionfish – an invader first observed off the Florida coast in the 1980s − is spreading through the north-west Atlantic. Temperature is the key determinant for a fish on the move. Fisheries biologist Paula Whitfield, of the National Oceanic and Atmospheric Administration’s National Centres for Coastal Ocean Science, and colleagues report in the journal Marine Ecology Progress Series that they surveyed 40 species of fish off the reefs of North Carolina.

Tropical species

These reefs have always been home both to temperate and tropical species, at the limits of their ranges. But now the reefs are becoming more tropical − and so is the local population. “Along the North Carolina coast, warming water temperatures may allow the expansion of tropical fish species, such as lionfish, into areas that were previously uninhabitable due to cold winter temperatures,” Whitfield says. “The temperature thresholds collected in this study will allow us to detect and estimate fish community changes related to water temperature.” The lionfish tends to prefer water warmer than 15.2°C, and so normally inhabits the warm currents of the deeper waters in the temperate Atlantic. It is a carnivore that seems to enjoy a wide range of prey. It makes itself at home in a wide variety of habitat, and is considered a serious threat to other species of reef fish. – Climate News Network