Tag Archives: Carbon Dioxide

Restoring forests rules out growing crops

Restoring forests is helpful, but planting crops to do so is not. Only one of these options soaks up enough atmospheric carbon.

LONDON, 15 April, 2019 − Nations of the world are committed to restoring forests covering an area the size of India to soak up carbon dioxide and combat climate change. But British scientists have identified a serious flaw in the plan.

“Two-thirds of the area committed to global reforestation for carbon storage is slated to grow crops,” they write in the journal Nature. “This raises serious concerns.”

Their argument is simple. To limit global warming to no more than 1.5°C by the end of the century requires both rapid cuts in emissions of carbon dioxide from fossil fuel use, and investment in efficient ways of removing CO2 from the atmosphere.

Altogether 43 tropical and subtropical nations have pledged to restore 350 million hectares of forest to remove 42 billion tonnes of carbon from the atmosphere by 2100.

Little natural forest

Many of them, including Brazil, China and India, have already committed to 292 million hectares of new canopy. But in their analysis of the plans published so far, the scientists say that only 34% of this accumulated area would go back to natural forest.

Another 45% would be covered by plantations of one species harvested for biomass or timber, and 21% would be devoted to agroforestry: a mix of crops sheltered by stands of woodland.

In their calculations, this altogether would remove only 16 bn tonnes of carbon. That is because natural forests restored and subsequently protected would hold 40 times the carbon of a monoculture plantation and six times more than any mix of trees and crops.

“There is a scandal here,” said Simon Lewis, a geographer at University College London, who led the analysis. “To most people, forest restoration means bringing back natural forests, but policy makers are calling vast monocultures ‘forest restoration.’ And worse, the advertised climate benefits are absent.”

“To most people, forest restoration means bringing back natural forests, but policy makers are calling vast monocultures ‘forest restoration’”

Forests are only part of the answer to the challenge of containing climate change. To keep to the promise made by 195 nations in Paris in 2015, humankind has to find ways to remove 730 bn tonnes of CO2 from the atmosphere, which translates to 199 bn tonnes of carbon.

If the world found ways to boost the total area of global forest, woodland and woody savannahs, this could absorb perhaps a quarter of the total needed to keep planetary warming to no more than 1.5°C. And many countries have signed up to convert degraded land to new tree canopy.

“But will this policy work?” the scientists ask. “We show that under current plans, it will not. A closer look at countries’ reports reveals that almost half the pledged area is set to become plantations of commercial trees.”

Their point is that plantations can support local economies, but are poorer at storing carbon. Natural forests require little or no disturbance from humans, whereas the regular clearing and harvesting of plantations releases stored carbon dioxide back into the atmosphere every 10 or 20 years, while natural forests go on sequestering the greenhouse gas for decades. Natural regeneration is the cheapest and easiest option.

Land use shift

Most of the monoculture commitments are in large countries such as Brazil, China, Indonesia, Nigeria and the Democratic Republic of the Congo. The scientists suggest such plans have been insufficiently thought through. Drastic increases in tropical plantation for commercial crops would mark a major shift in global land use and could be accompanied by a fall in prices, with potentially unsatisfactory economic consequences.

And, they argue, policymakers are in any case misinterpreting the term forest restoration: it should not include plantations of a single species, such as eucalypt or rubber, which would do little for carbon sequestration. If commercial plantations were planted across the whole 350 million hectares, the entire crop would soak up and store just one billion tonnes of carbon.

“Of course new natural forests alone are not sufficient to meet our climate goals,” said Charlotte Wheeler of the University of Edinburgh, another of the authors. “Emissions from fossil fuels and deforestation must also stop.

“Other ways to remove carbon from the atmosphere are also needed. But no scenario has been produced that keeps climate change below dangerous levels without the large-scale restoration of natural forests.” − Climate News Network

Restoring forests is helpful, but planting crops to do so is not. Only one of these options soaks up enough atmospheric carbon.

LONDON, 15 April, 2019 − Nations of the world are committed to restoring forests covering an area the size of India to soak up carbon dioxide and combat climate change. But British scientists have identified a serious flaw in the plan.

“Two-thirds of the area committed to global reforestation for carbon storage is slated to grow crops,” they write in the journal Nature. “This raises serious concerns.”

Their argument is simple. To limit global warming to no more than 1.5°C by the end of the century requires both rapid cuts in emissions of carbon dioxide from fossil fuel use, and investment in efficient ways of removing CO2 from the atmosphere.

Altogether 43 tropical and subtropical nations have pledged to restore 350 million hectares of forest to remove 42 billion tonnes of carbon from the atmosphere by 2100.

Little natural forest

Many of them, including Brazil, China and India, have already committed to 292 million hectares of new canopy. But in their analysis of the plans published so far, the scientists say that only 34% of this accumulated area would go back to natural forest.

Another 45% would be covered by plantations of one species harvested for biomass or timber, and 21% would be devoted to agroforestry: a mix of crops sheltered by stands of woodland.

In their calculations, this altogether would remove only 16 bn tonnes of carbon. That is because natural forests restored and subsequently protected would hold 40 times the carbon of a monoculture plantation and six times more than any mix of trees and crops.

“There is a scandal here,” said Simon Lewis, a geographer at University College London, who led the analysis. “To most people, forest restoration means bringing back natural forests, but policy makers are calling vast monocultures ‘forest restoration.’ And worse, the advertised climate benefits are absent.”

“To most people, forest restoration means bringing back natural forests, but policy makers are calling vast monocultures ‘forest restoration’”

Forests are only part of the answer to the challenge of containing climate change. To keep to the promise made by 195 nations in Paris in 2015, humankind has to find ways to remove 730 bn tonnes of CO2 from the atmosphere, which translates to 199 bn tonnes of carbon.

If the world found ways to boost the total area of global forest, woodland and woody savannahs, this could absorb perhaps a quarter of the total needed to keep planetary warming to no more than 1.5°C. And many countries have signed up to convert degraded land to new tree canopy.

“But will this policy work?” the scientists ask. “We show that under current plans, it will not. A closer look at countries’ reports reveals that almost half the pledged area is set to become plantations of commercial trees.”

Their point is that plantations can support local economies, but are poorer at storing carbon. Natural forests require little or no disturbance from humans, whereas the regular clearing and harvesting of plantations releases stored carbon dioxide back into the atmosphere every 10 or 20 years, while natural forests go on sequestering the greenhouse gas for decades. Natural regeneration is the cheapest and easiest option.

Land use shift

Most of the monoculture commitments are in large countries such as Brazil, China, Indonesia, Nigeria and the Democratic Republic of the Congo. The scientists suggest such plans have been insufficiently thought through. Drastic increases in tropical plantation for commercial crops would mark a major shift in global land use and could be accompanied by a fall in prices, with potentially unsatisfactory economic consequences.

And, they argue, policymakers are in any case misinterpreting the term forest restoration: it should not include plantations of a single species, such as eucalypt or rubber, which would do little for carbon sequestration. If commercial plantations were planted across the whole 350 million hectares, the entire crop would soak up and store just one billion tonnes of carbon.

“Of course new natural forests alone are not sufficient to meet our climate goals,” said Charlotte Wheeler of the University of Edinburgh, another of the authors. “Emissions from fossil fuels and deforestation must also stop.

“Other ways to remove carbon from the atmosphere are also needed. But no scenario has been produced that keeps climate change below dangerous levels without the large-scale restoration of natural forests.” − Climate News Network

CO2 levels pass 3-million-year record

The modern world is about to pass a temperature peak dating back for millions of years – because CO2 levels have already passed an ancient record..

LONDON, 8 April, 2019 – German scientists have confirmed, once again, that carbon dioxide is reaching concentrations unprecedented on any human time scale, with CO2 levels in the atmosphere already higher than they have been for at least three million years.

And their computer simulations – backed up by analysis of ocean sediments that tell a tale of changing temperatures and greenhouse gas levels – show that before the century’s close the world will become warmer than at any time in the last three million years.

The last time planetary temperatures reached a level higher than the target set by 195 nations in Paris in 2015 was during a bygone geological period, the Pliocene.

“It seems we are now pushing our home planet beyond any climatic conditions experienced during the entire current geological period, the Quaternary,” said Matteo Willeit of the Potsdam Institute for Climate Impact Research.

“Our results imply a strong sensitivity of the Earth system to relatively small changes in atmospheric CO2. As fascinating as this is, it is also worrying”

“A period that started almost three million years ago and saw human civilisation beginning only 11,000 years ago. So the modern change we see is big, really big, even by the standards of Earth history.”

He and colleagues report in the journal Science Advances  that they made a numerical model of all the astronomical and geological data available for the last few million years and fed in algorithms to represent the physics and chemistry of planet Earth.

So they had a simulation of a rocky planet complete with active volcanoes that emit carbon dioxide with their magma, on a journey many times around a slowly-changing elliptical orbit that subtly changed the levels of sunshine that slammed into the rocks, oceans and forests – patterns of change called the Milankovitch cycles, long implicated in periodic shifts in planetary climate.

They also fed in data about sediments in the high latitudes: important because ice sheets advance more easily over gravel than bedrock, and atmospheric dust from such attrition makes ice surfaces darker and more vulnerable to melting. The result: confirmation of one thing already observed and another much feared.

Carbon ratio leaps

At a time in the astronomical cycle when Earthlings might expect a slow return of the Ice Ages, human action over the last two centuries – the profligate combustion of fossil fuels that emit greenhouse gases, the wholesale clearance of the great forests that absorb atmospheric carbon – has already lifted carbon dioxide ratios from a long-term average of around 280 parts per million to more than 400 ppm.

Human action has also raised long-term average planetary temperatures by a whole degree Celsius, with more warming on the way.

A new Ice Age seems increasingly unlikely, and other researchers have already pointed to the Pliocene data as a soon-to-be-exceeded record.

Entirely different studies have shown the world to be on course to exceed the 2°C limit, so the research confirms other findings and delivers a test of the reliability of evidence from the past. It also backs up the value of simulation as an increasingly reliable form of climate forecasting.

CO2’s key role

“We know from the analysis of sediments on the bottom of our seas about past ocean temperatures and ice volumes, but so far the role of CO2 in shaping the glacial cycles has not been fully understood,” said Dr Willeit.

“It is a breakthrough that we can now show in computer simulations that changes in CO2 levels were a main driver of the Ice Ages, together with variations of how the Earth orbits around the sun, the so-called Milankovitch cycles. These are actually not just simulations: we compared our results with hard data from the deep sea, and they prove to be in good agreement,” he said.

“Our results imply a strong sensitivity of the Earth system to relatively small changes in atmospheric CO2. As fascinating as this is, it is also worrying.” – Climate News Network

The modern world is about to pass a temperature peak dating back for millions of years – because CO2 levels have already passed an ancient record..

LONDON, 8 April, 2019 – German scientists have confirmed, once again, that carbon dioxide is reaching concentrations unprecedented on any human time scale, with CO2 levels in the atmosphere already higher than they have been for at least three million years.

And their computer simulations – backed up by analysis of ocean sediments that tell a tale of changing temperatures and greenhouse gas levels – show that before the century’s close the world will become warmer than at any time in the last three million years.

The last time planetary temperatures reached a level higher than the target set by 195 nations in Paris in 2015 was during a bygone geological period, the Pliocene.

“It seems we are now pushing our home planet beyond any climatic conditions experienced during the entire current geological period, the Quaternary,” said Matteo Willeit of the Potsdam Institute for Climate Impact Research.

“Our results imply a strong sensitivity of the Earth system to relatively small changes in atmospheric CO2. As fascinating as this is, it is also worrying”

“A period that started almost three million years ago and saw human civilisation beginning only 11,000 years ago. So the modern change we see is big, really big, even by the standards of Earth history.”

He and colleagues report in the journal Science Advances  that they made a numerical model of all the astronomical and geological data available for the last few million years and fed in algorithms to represent the physics and chemistry of planet Earth.

So they had a simulation of a rocky planet complete with active volcanoes that emit carbon dioxide with their magma, on a journey many times around a slowly-changing elliptical orbit that subtly changed the levels of sunshine that slammed into the rocks, oceans and forests – patterns of change called the Milankovitch cycles, long implicated in periodic shifts in planetary climate.

They also fed in data about sediments in the high latitudes: important because ice sheets advance more easily over gravel than bedrock, and atmospheric dust from such attrition makes ice surfaces darker and more vulnerable to melting. The result: confirmation of one thing already observed and another much feared.

Carbon ratio leaps

At a time in the astronomical cycle when Earthlings might expect a slow return of the Ice Ages, human action over the last two centuries – the profligate combustion of fossil fuels that emit greenhouse gases, the wholesale clearance of the great forests that absorb atmospheric carbon – has already lifted carbon dioxide ratios from a long-term average of around 280 parts per million to more than 400 ppm.

Human action has also raised long-term average planetary temperatures by a whole degree Celsius, with more warming on the way.

A new Ice Age seems increasingly unlikely, and other researchers have already pointed to the Pliocene data as a soon-to-be-exceeded record.

Entirely different studies have shown the world to be on course to exceed the 2°C limit, so the research confirms other findings and delivers a test of the reliability of evidence from the past. It also backs up the value of simulation as an increasingly reliable form of climate forecasting.

CO2’s key role

“We know from the analysis of sediments on the bottom of our seas about past ocean temperatures and ice volumes, but so far the role of CO2 in shaping the glacial cycles has not been fully understood,” said Dr Willeit.

“It is a breakthrough that we can now show in computer simulations that changes in CO2 levels were a main driver of the Ice Ages, together with variations of how the Earth orbits around the sun, the so-called Milankovitch cycles. These are actually not just simulations: we compared our results with hard data from the deep sea, and they prove to be in good agreement,” he said.

“Our results imply a strong sensitivity of the Earth system to relatively small changes in atmospheric CO2. As fascinating as this is, it is also worrying.” – Climate News Network

Europe’s food imports devour rainforests

Human appetites drive global rainforest destruction. Now science has measured how Europe’s food imports leave scorched tropical soils and greenhouse gases.

LONDON, 5 April, 2019 − European scientists have worked out how European consumers can reduce tropical forest loss and cut down greenhouse emissions in other countries.

One: stop buying beef, especially from Brazil. And two: be sparing with the oil from tropical palms and soybean plantations.

In theory, this should be news to nobody. Forests absorb carbon dioxide from the atmosphere and slow global warming. But forests that have been felled for cattle-grazing or burned and cleared for oil plantations are net emitters of carbon into the atmosphere to accelerate global warming and precipitate yet more dangerous climate change.

But in two related publications, researchers have looked beyond the theory to identify the responsibility of one geopolitical grouping for precise volumes of greenhouse gas emissions in faraway places.

First they report, in the journal Global Environmental Change, that they looked at the loss of tropical rainforests, and then at the ways in which the felled or scorched forests have been used, for food production.

“If you give tropical countries support . . . to protect the rainforest, as well as giving farmers alternatives to deforestation to increase production, it can have a big impact”

And then, in the journal Environmental Research Letters, they took the measure of carbon dioxide emissions that might be linked to food production from the destroyed rainforest, and then worked out from world trade data where that food went.

The European Union as a whole is a huge importer of food. And the conclusion is that one-sixth of the emissions from a typical EU diet can be traced directly back to deforestation in the tropics.

“In effect, you could say that the EU imports large amounts of deforestation every year. If the EU really wants to achieve climate goals, it must set harder environmental standards on those who export food to the EU,” said Martin Persson of Chalmers University of Technology in Sweden.

And his co-author Florence Pendrill, also at Chalmers, said: “We can see that more than half of deforestation is due to the production of food and animal feed, such as beef, soy beans and palm oil.

Food exports rising

“There is a big variation between different countries and goods, but overall, exports account for about a fourth of that deforestation which is connected to food production. And these figures have increased during the period we have looked at.”

The principles are clear: like the shift away from dependence on fossil fuels, the preservation and growth of the world’s forests is one of the priorities in slowing greenhouse gas emissions and limiting climate change.

Researchers have repeatedly stressed that a shift away from a meat diet could reduce emissions; a global switch to crops rather than cattle would mean greater output from existing farmland and help save forests everywhere.

In general, many developed countries have begun to enlarge the space covered by forest canopy. But the tropical rainforests remain at risk: from drought and wildfire linked to climate change, and from direct human invasion in pursuit of yet more space to exploit for cattle ranches and oil plantations. Greenhouse gas emissions from rainforests are on the increase.

Extending the rules

The European Union already has strict rules about the provision of timber and wood products from exporting countries: these have already helped protect some areas of the vulnerable tropical rainforests. The next challenge is to see whether such regulation can be effectively tailored to food imports.

The scientists found that between 2010 and 2014, around 2.6 billion tonnes of carbon dioxide escaped from ranches, croplands and plantations on cleared forest land. Of this, 900 million tonnes of carbon dioxide came from cattle meat, much of it from Brazil, and 600 million from palm oil and soybean plantations, almost half of this from Indonesia.

“Now, as the connection between food production and deforestation is made clearer, we should start to discuss possibilities for the EU to adopt similar regulations for food imports. Quite simply, deforestation should end up costing the producer more,” said Dr Pendrill.

“If you give tropical countries support in their work to protect the rainforest, as well as giving farmers alternatives to deforestation to increase production, it can have a big impact.” − Climate News Network

Human appetites drive global rainforest destruction. Now science has measured how Europe’s food imports leave scorched tropical soils and greenhouse gases.

LONDON, 5 April, 2019 − European scientists have worked out how European consumers can reduce tropical forest loss and cut down greenhouse emissions in other countries.

One: stop buying beef, especially from Brazil. And two: be sparing with the oil from tropical palms and soybean plantations.

In theory, this should be news to nobody. Forests absorb carbon dioxide from the atmosphere and slow global warming. But forests that have been felled for cattle-grazing or burned and cleared for oil plantations are net emitters of carbon into the atmosphere to accelerate global warming and precipitate yet more dangerous climate change.

But in two related publications, researchers have looked beyond the theory to identify the responsibility of one geopolitical grouping for precise volumes of greenhouse gas emissions in faraway places.

First they report, in the journal Global Environmental Change, that they looked at the loss of tropical rainforests, and then at the ways in which the felled or scorched forests have been used, for food production.

“If you give tropical countries support . . . to protect the rainforest, as well as giving farmers alternatives to deforestation to increase production, it can have a big impact”

And then, in the journal Environmental Research Letters, they took the measure of carbon dioxide emissions that might be linked to food production from the destroyed rainforest, and then worked out from world trade data where that food went.

The European Union as a whole is a huge importer of food. And the conclusion is that one-sixth of the emissions from a typical EU diet can be traced directly back to deforestation in the tropics.

“In effect, you could say that the EU imports large amounts of deforestation every year. If the EU really wants to achieve climate goals, it must set harder environmental standards on those who export food to the EU,” said Martin Persson of Chalmers University of Technology in Sweden.

And his co-author Florence Pendrill, also at Chalmers, said: “We can see that more than half of deforestation is due to the production of food and animal feed, such as beef, soy beans and palm oil.

Food exports rising

“There is a big variation between different countries and goods, but overall, exports account for about a fourth of that deforestation which is connected to food production. And these figures have increased during the period we have looked at.”

The principles are clear: like the shift away from dependence on fossil fuels, the preservation and growth of the world’s forests is one of the priorities in slowing greenhouse gas emissions and limiting climate change.

Researchers have repeatedly stressed that a shift away from a meat diet could reduce emissions; a global switch to crops rather than cattle would mean greater output from existing farmland and help save forests everywhere.

In general, many developed countries have begun to enlarge the space covered by forest canopy. But the tropical rainforests remain at risk: from drought and wildfire linked to climate change, and from direct human invasion in pursuit of yet more space to exploit for cattle ranches and oil plantations. Greenhouse gas emissions from rainforests are on the increase.

Extending the rules

The European Union already has strict rules about the provision of timber and wood products from exporting countries: these have already helped protect some areas of the vulnerable tropical rainforests. The next challenge is to see whether such regulation can be effectively tailored to food imports.

The scientists found that between 2010 and 2014, around 2.6 billion tonnes of carbon dioxide escaped from ranches, croplands and plantations on cleared forest land. Of this, 900 million tonnes of carbon dioxide came from cattle meat, much of it from Brazil, and 600 million from palm oil and soybean plantations, almost half of this from Indonesia.

“Now, as the connection between food production and deforestation is made clearer, we should start to discuss possibilities for the EU to adopt similar regulations for food imports. Quite simply, deforestation should end up costing the producer more,” said Dr Pendrill.

“If you give tropical countries support in their work to protect the rainforest, as well as giving farmers alternatives to deforestation to increase production, it can have a big impact.” − Climate News Network

Mosquito risk to health may double by 2100

As the world warms, the horizons also widen for the mosquito risk to health, putting another billion people in jeopardy.

LONDON, 1 April, 2019 − Within 80 years the health of twice as many people as today could face a serious mosquito risk − and not only in the tropics.

One billion people are already in danger of mosquito-borne disease. As the world warms and climates become more hospitable to the insects that transmit dengue fever, yellow fever, Zika and other fearful viruses, that number could double by the end of the century.

And as Aedes aegypti and Aedes albopictus extend their range to the north and the south, and higher up the hill regions, tropical infections that already kill millions will spread into the temperate zones.

“Climate change is the largest and most comprehensive threat to global health security . . .  after the Zika outbreak in Brazil in 2015, we’re especially worried about what comes next”

At some point in the next 50 years, according to a study in the Public Library of Science journal PLOS Neglected Tropical Diseases, one billion people could become newly exposed not just to dengue and yellow fever, but to emerging diseases such as chikungunya, Zika, West Nile and Japanese encephalitis, all carried by just two species of mosquito.

“Climate change will have a profound effect on the global distribution and burden of infectious diseases,” the authors warn. “Current knowledge suggests that the range of mosquito-borne diseases could expand dramatically in response to climate change.”

As temperatures go up – the planet is already 1°C warmer on average than it has been for most of human history, thanks to profligate use of fossil fuels to pump greenhouse gases into the atmosphere, and is on course to hit 3°C warmer by 2100 – so does the scope for disease transmission by insects that flourish in a range of temperatures.

No let-up

Infections could begin to happen year-round in the tropics, and some people could be at risk during the warmer seasons almost everywhere else. Infections, too, could become more intense.

Rising temperatures open up new ranges for carriers of potentially lethal disease, and the latest study takes a closer look at what climate models predict about disease transmission by just two species.

“These diseases, which we think of as strictly tropical, have been showing up already in areas with suitable climates, such as Florida, because humans are very good at moving both bugs and their pathogens around the globe,” said Sadie Ryan, a medical geographer at the University of Florida, who led the study.

Mosquitoes grounded?

And her co-author Colin Carlson, a biologist at Georgetown University in Washington DC, said: “Climate change is the largest and most comprehensive threat to global health security. Mosquitoes are only part of the challenge, but after the Zika outbreak in Brazil in 2015, we’re especially worried about what comes next.”

Paradoxically, rising temperatures could be good news for some at-risk populations: both the Anopheles mosquito that carries the malaria parasite and the Aedes that is host to a number of diseases are most dangerous within a range of temperatures: as the thermometer rises, it could become too hot for malaria transmission in some places, or even too hot for mosquitoes.

“This might sound like a good news, bad news situation, but it’s all bad news if we end up in the worst timeline for climate change,” said Dr Carlson. “Any scenario where a region gets too warm to transmit dengue is one where we have different but equally severe threats in other health sectors.” − Climate News Network

As the world warms, the horizons also widen for the mosquito risk to health, putting another billion people in jeopardy.

LONDON, 1 April, 2019 − Within 80 years the health of twice as many people as today could face a serious mosquito risk − and not only in the tropics.

One billion people are already in danger of mosquito-borne disease. As the world warms and climates become more hospitable to the insects that transmit dengue fever, yellow fever, Zika and other fearful viruses, that number could double by the end of the century.

And as Aedes aegypti and Aedes albopictus extend their range to the north and the south, and higher up the hill regions, tropical infections that already kill millions will spread into the temperate zones.

“Climate change is the largest and most comprehensive threat to global health security . . .  after the Zika outbreak in Brazil in 2015, we’re especially worried about what comes next”

At some point in the next 50 years, according to a study in the Public Library of Science journal PLOS Neglected Tropical Diseases, one billion people could become newly exposed not just to dengue and yellow fever, but to emerging diseases such as chikungunya, Zika, West Nile and Japanese encephalitis, all carried by just two species of mosquito.

“Climate change will have a profound effect on the global distribution and burden of infectious diseases,” the authors warn. “Current knowledge suggests that the range of mosquito-borne diseases could expand dramatically in response to climate change.”

As temperatures go up – the planet is already 1°C warmer on average than it has been for most of human history, thanks to profligate use of fossil fuels to pump greenhouse gases into the atmosphere, and is on course to hit 3°C warmer by 2100 – so does the scope for disease transmission by insects that flourish in a range of temperatures.

No let-up

Infections could begin to happen year-round in the tropics, and some people could be at risk during the warmer seasons almost everywhere else. Infections, too, could become more intense.

Rising temperatures open up new ranges for carriers of potentially lethal disease, and the latest study takes a closer look at what climate models predict about disease transmission by just two species.

“These diseases, which we think of as strictly tropical, have been showing up already in areas with suitable climates, such as Florida, because humans are very good at moving both bugs and their pathogens around the globe,” said Sadie Ryan, a medical geographer at the University of Florida, who led the study.

Mosquitoes grounded?

And her co-author Colin Carlson, a biologist at Georgetown University in Washington DC, said: “Climate change is the largest and most comprehensive threat to global health security. Mosquitoes are only part of the challenge, but after the Zika outbreak in Brazil in 2015, we’re especially worried about what comes next.”

Paradoxically, rising temperatures could be good news for some at-risk populations: both the Anopheles mosquito that carries the malaria parasite and the Aedes that is host to a number of diseases are most dangerous within a range of temperatures: as the thermometer rises, it could become too hot for malaria transmission in some places, or even too hot for mosquitoes.

“This might sound like a good news, bad news situation, but it’s all bad news if we end up in the worst timeline for climate change,” said Dr Carlson. “Any scenario where a region gets too warm to transmit dengue is one where we have different but equally severe threats in other health sectors.” − Climate News Network

Hunger is growing as the world warms faster

Climate change is speeding up, and among its malign impacts is a setback for efforts to feed the world: hunger is growing again.

LONDON, 29 March, 2019 − The global threat of hunger is growing again after years of progress in reducing it, the United Nations says, because of the effects of climate change.

It says this is just one aspect of a wider acceleration in the pace of the changes wrought by the world’s unremitting consumption of fossil fuels and the consequential rise in global temperatures..

The evidence that hunger and malnutrition are once again on the rise is published in a new report from the World Meteorological Organization (WMO) on the state of the global climate in 2018.

The report, drawing on material from scientists, UN agencies and countries’ own meteorological services, says the physical signs and the impacts of climate change are speeding up as record greenhouse gas concentrations drive global temperatures towards increasingly dangerous levels.

“New evidence shows a continuing rise in world hunger after a prolonged decline . . . ”

Highlighting record sea level rise and exceptionally high land and ocean temperatures over the past four years, the report warns that this warming trend has lasted since the start of this century and is expected to continue.

Carbon dioxide levels, which were at 357.0 parts per million when the first statement in the series was published in 1994, keep rising − to 405.5 ppm in 2017. Greenhouse gas concentrations for 2018 and 2019 are expected to show a further increase.

The start of 2019 has seen warm record daily winter temperatures in Europe, unusual cold in North America and searing heatwaves in Australia. Arctic and Antarctic ice extent is yet again well below average.

In a statement the UN secretary-general, António Guterres, writes that the data released in the report “give cause for great concern. The past four years were the warmest on record, with the global average surface temperature in 2018 approximately 1°C above the pre-industrial baseline … There is no longer any time for delay.”

Four warming years

The WMO secretary-general, Petteri Taalas, says: “Key findings of this statement include the striking consecutive record warming recorded from 2015 through 2018, the continuous upward trend in the atmospheric concentrations of the major greenhouse gases, the increasing rate of sea level rise and the loss of sea ice in both northern and southern polar regions.”

One particular concern highlighted is food security. In the words of the report, “exposure of the agriculture sector to climate extremes is threatening to reverse gains made in ending malnutrition.

“New evidence shows a continuing rise in world hunger  after a prolonged decline, according to data compiled by UN agencies including the Food and Agriculture Organization (FAO) and World Food Programme.

“In 2017, the number of undernourished people was estimated to have increased to 821 million, partly due to severe droughts associated with the strong El Niño of 2015–2016.”

Climate refugees

The FAO says the absolute number of undernourished people − those facing chronic food deprivation − reached  nearly 821 m in 2017, from around 804 m in 2016.

The WMO report also singles out the plight of those forced by climate change to leave their homes and become refugees, either within their own countries or abroad. Out of 17.7 m people classified as internally displaced persons (IDPs) tracked by the International Organization for Migration, it says, by September 2018 over 2 m people had been displaced by disasters linked to weather and climate events.

According to the UN refugee agency UNHCR’s Protection and Return Monitoring Network, about 883,000 new internal displacements were recorded between January and December 2018, of which 32% were associated with flooding and 29% with drought.

Hundreds of thousands of Rohingya refugees were affected by what the UN calls “secondary displacement”, caused by extreme events, heavy rain, flooding and landslides.

More acid seas

The WMO also expresses concern about a range of impacts of climate change on the global environment, including reduced levels of oxygen in the oceans. Since the middle of the last century there has been an estimated 1-2% decrease in the amount of oxygen in the world’s oceans, according to UNESCO’s Intergovernmental Oceanographic Commission (UNESCO-IOC).

In the past decade the oceans have absorbed around 30% of CO2 emissions of human origin. Absorbed CO2 reacts with seawater and changes the pH of the ocean. This process, known as ocean acidification, can affect the ability of marine organisms such as molluscs and reef-building corals, to build and maintain shells and skeletal material.

Observations in the open ocean over the last 30 years have shown a clear trend of decreasing pH. In line with previous reports and projections, ocean acidification is ongoing and the global pH levels continue to decrease, according to UNESCO-IOC. One recent report suggested possible alarming future impacts.

The State of the Climate report will be one of WMO’s contributions to the UN’s Climate Action Summit on 23 September. − Climate News Network

Climate change is speeding up, and among its malign impacts is a setback for efforts to feed the world: hunger is growing again.

LONDON, 29 March, 2019 − The global threat of hunger is growing again after years of progress in reducing it, the United Nations says, because of the effects of climate change.

It says this is just one aspect of a wider acceleration in the pace of the changes wrought by the world’s unremitting consumption of fossil fuels and the consequential rise in global temperatures..

The evidence that hunger and malnutrition are once again on the rise is published in a new report from the World Meteorological Organization (WMO) on the state of the global climate in 2018.

The report, drawing on material from scientists, UN agencies and countries’ own meteorological services, says the physical signs and the impacts of climate change are speeding up as record greenhouse gas concentrations drive global temperatures towards increasingly dangerous levels.

“New evidence shows a continuing rise in world hunger after a prolonged decline . . . ”

Highlighting record sea level rise and exceptionally high land and ocean temperatures over the past four years, the report warns that this warming trend has lasted since the start of this century and is expected to continue.

Carbon dioxide levels, which were at 357.0 parts per million when the first statement in the series was published in 1994, keep rising − to 405.5 ppm in 2017. Greenhouse gas concentrations for 2018 and 2019 are expected to show a further increase.

The start of 2019 has seen warm record daily winter temperatures in Europe, unusual cold in North America and searing heatwaves in Australia. Arctic and Antarctic ice extent is yet again well below average.

In a statement the UN secretary-general, António Guterres, writes that the data released in the report “give cause for great concern. The past four years were the warmest on record, with the global average surface temperature in 2018 approximately 1°C above the pre-industrial baseline … There is no longer any time for delay.”

Four warming years

The WMO secretary-general, Petteri Taalas, says: “Key findings of this statement include the striking consecutive record warming recorded from 2015 through 2018, the continuous upward trend in the atmospheric concentrations of the major greenhouse gases, the increasing rate of sea level rise and the loss of sea ice in both northern and southern polar regions.”

One particular concern highlighted is food security. In the words of the report, “exposure of the agriculture sector to climate extremes is threatening to reverse gains made in ending malnutrition.

“New evidence shows a continuing rise in world hunger  after a prolonged decline, according to data compiled by UN agencies including the Food and Agriculture Organization (FAO) and World Food Programme.

“In 2017, the number of undernourished people was estimated to have increased to 821 million, partly due to severe droughts associated with the strong El Niño of 2015–2016.”

Climate refugees

The FAO says the absolute number of undernourished people − those facing chronic food deprivation − reached  nearly 821 m in 2017, from around 804 m in 2016.

The WMO report also singles out the plight of those forced by climate change to leave their homes and become refugees, either within their own countries or abroad. Out of 17.7 m people classified as internally displaced persons (IDPs) tracked by the International Organization for Migration, it says, by September 2018 over 2 m people had been displaced by disasters linked to weather and climate events.

According to the UN refugee agency UNHCR’s Protection and Return Monitoring Network, about 883,000 new internal displacements were recorded between January and December 2018, of which 32% were associated with flooding and 29% with drought.

Hundreds of thousands of Rohingya refugees were affected by what the UN calls “secondary displacement”, caused by extreme events, heavy rain, flooding and landslides.

More acid seas

The WMO also expresses concern about a range of impacts of climate change on the global environment, including reduced levels of oxygen in the oceans. Since the middle of the last century there has been an estimated 1-2% decrease in the amount of oxygen in the world’s oceans, according to UNESCO’s Intergovernmental Oceanographic Commission (UNESCO-IOC).

In the past decade the oceans have absorbed around 30% of CO2 emissions of human origin. Absorbed CO2 reacts with seawater and changes the pH of the ocean. This process, known as ocean acidification, can affect the ability of marine organisms such as molluscs and reef-building corals, to build and maintain shells and skeletal material.

Observations in the open ocean over the last 30 years have shown a clear trend of decreasing pH. In line with previous reports and projections, ocean acidification is ongoing and the global pH levels continue to decrease, according to UNESCO-IOC. One recent report suggested possible alarming future impacts.

The State of the Climate report will be one of WMO’s contributions to the UN’s Climate Action Summit on 23 September. − Climate News Network

Worse tropical winds will kill more trees

More greenhouse gases mean worse tropical winds and fiercer storms. That could mean more forest damage . . . and more greenhouse gas emissions . . .

LONDON, 28 March, 2019 − Worse tropical winds will spell worse danger to forests, in a cycle that feeds on itself. Hurricane Maria, which in 2017 slammed into Puerto Rico, shut down the electricity supply for the entire US island of 3.3 million people, and claimed almost 3,000 lives. And it also killed or damaged at least 20 million trees, or possibly 40 million.

If what happened in the track of Maria is a pointer to the future, then hurricanes, typhoons and tropical cyclones will join drought, wildfire and men with chainsaws as a new threat to the world’s tropical forests, the biggest absorbers of carbon on the terrestrial surface.

Living forests absorb carbon. Dying and decaying trees release greenhouse gases. The damage by Maria has already been estimated to have released 5.75 million tonnes of carbon to the atmosphere. This is about one-fortieth of all the carbon taken up by all the forests in the US.

“The expected changes in hurricane winds and rainfall may have profound consequences for the long-term resilience of tropical forests in the North Atlantic basin”

Hurricanes are linked with rising sea surface temperatures. Researchers have been warning for decades that in a warming world, extremes of heat, drought, flood and windstorm will become more destructive. So Hurricane Maria could be a taste of things to come.

“These hurricanes are going to kill more trees,” said Maria Uriarte, of the Earth Institute of Columbia University. “They’re going to break more trees. The factors that protected many trees in the past will no longer apply. Forests will become shorter and smaller because they won’t have time to regrow, and they will be less diverse.”

Maria blew into Puerto Rico in October 2017, with winds of up to 250 kms an hour. It dropped 500 mm of rain to become the island’s worst storm for 90 years.

To make their estimate of the destruction, Professor Uriarte and colleagues surveyed a 16-hectare plot of the island’s El Yunque national forest near the capital, San Juan: a plot that has been monitored after violent windstorm assault in 1989 by Hurricane Hugo and then in 1998 by Hurricane Georges.

Much fiercer impact

They report in the journal Nature Communications that Hurricane Maria killed twice as many trees outright as previous storms, and snapped more than three times as many trunks. Some species experienced breakage rates of up to 12 times that of previous hurricanes. Among them, and unexpectedly, were some of the slowest-growing, most valuable hardwoods. About half of all trees with broken trunks are expected to die within two or three years.

Some species survived well: among them the sierra palm, a tree able to bend with the wind, and if stripped sprout again from the top. Such species could be the inheritors of future hurricanes and grow quickly to take advantage of cleared forest space. So future forests could be dominated by shorter, and less diverse, foliage.

And the future is unpromising. Atlantic Ocean sea surface temperatures are rising, and climate simulations predict that by 2100 the highest sustained hurricane winds could increase by 15%. Warmer air can hold more moisture, so rainfall near storm centres could increase by 20%. Extreme winds fell trees; rain destabilises soil and makes uprooting easier.

“Maria transformed tropical forests across the island into leafless tangles of damaged and downed trees,” the researchers write. And they warn: “The expected changes in hurricane winds and rainfall may have profound consequences for the long-term resilience of tropical forests in the North Atlantic basin.” − Climate News Network

More greenhouse gases mean worse tropical winds and fiercer storms. That could mean more forest damage . . . and more greenhouse gas emissions . . .

LONDON, 28 March, 2019 − Worse tropical winds will spell worse danger to forests, in a cycle that feeds on itself. Hurricane Maria, which in 2017 slammed into Puerto Rico, shut down the electricity supply for the entire US island of 3.3 million people, and claimed almost 3,000 lives. And it also killed or damaged at least 20 million trees, or possibly 40 million.

If what happened in the track of Maria is a pointer to the future, then hurricanes, typhoons and tropical cyclones will join drought, wildfire and men with chainsaws as a new threat to the world’s tropical forests, the biggest absorbers of carbon on the terrestrial surface.

Living forests absorb carbon. Dying and decaying trees release greenhouse gases. The damage by Maria has already been estimated to have released 5.75 million tonnes of carbon to the atmosphere. This is about one-fortieth of all the carbon taken up by all the forests in the US.

“The expected changes in hurricane winds and rainfall may have profound consequences for the long-term resilience of tropical forests in the North Atlantic basin”

Hurricanes are linked with rising sea surface temperatures. Researchers have been warning for decades that in a warming world, extremes of heat, drought, flood and windstorm will become more destructive. So Hurricane Maria could be a taste of things to come.

“These hurricanes are going to kill more trees,” said Maria Uriarte, of the Earth Institute of Columbia University. “They’re going to break more trees. The factors that protected many trees in the past will no longer apply. Forests will become shorter and smaller because they won’t have time to regrow, and they will be less diverse.”

Maria blew into Puerto Rico in October 2017, with winds of up to 250 kms an hour. It dropped 500 mm of rain to become the island’s worst storm for 90 years.

To make their estimate of the destruction, Professor Uriarte and colleagues surveyed a 16-hectare plot of the island’s El Yunque national forest near the capital, San Juan: a plot that has been monitored after violent windstorm assault in 1989 by Hurricane Hugo and then in 1998 by Hurricane Georges.

Much fiercer impact

They report in the journal Nature Communications that Hurricane Maria killed twice as many trees outright as previous storms, and snapped more than three times as many trunks. Some species experienced breakage rates of up to 12 times that of previous hurricanes. Among them, and unexpectedly, were some of the slowest-growing, most valuable hardwoods. About half of all trees with broken trunks are expected to die within two or three years.

Some species survived well: among them the sierra palm, a tree able to bend with the wind, and if stripped sprout again from the top. Such species could be the inheritors of future hurricanes and grow quickly to take advantage of cleared forest space. So future forests could be dominated by shorter, and less diverse, foliage.

And the future is unpromising. Atlantic Ocean sea surface temperatures are rising, and climate simulations predict that by 2100 the highest sustained hurricane winds could increase by 15%. Warmer air can hold more moisture, so rainfall near storm centres could increase by 20%. Extreme winds fell trees; rain destabilises soil and makes uprooting easier.

“Maria transformed tropical forests across the island into leafless tangles of damaged and downed trees,” the researchers write. And they warn: “The expected changes in hurricane winds and rainfall may have profound consequences for the long-term resilience of tropical forests in the North Atlantic basin.” − Climate News Network

Writer’s notes show climate impact on plants

The writer’s notes left by the US thinker and naturalist known as the sage of Walden Pond have yielded more evidence of climate change.

LONDON, 27 March, 2019 − Henry David Thoreau, author of the memoir Walden, or Life in the Woods, in 1854, did more than just observe the oaks, the aspens, the “golden-rods, pinweeds and graceful wild grasses”: he left precise writer’s notes on the natural world he found during his wilful exile in the Massachusetts wilderness.

And thanks to these, US researchers now know that as the world warms, the native ecosystem that Thoreau observed and recorded is out of step.

At the close of winter, the trees now leaf at least two weeks earlier. But the wildflowers that depend on their moment in the sun for a head start now form leaves only one week earlier.

Researchers from Tennessee, Massachusetts, Maine and New York State report in the journal Ecology Letters that they combined observations around Walden in 1852 with a sequence of observations made in 37 separate years up to 2018, and with separate field experiments in a Pennsylvania forest, to conclude that wildflowers could not keep pace

“Combining our work from Pittsburgh with Thoreau’s data revealed an overlooked yet critical implication of how our changing climate is affecting native wildflowers beloved by so many people,” said Mason Heberling, a botanist at the Carnegie Museum of Natural History in Pittsburgh, who led the research.

Novel science

The Oxford English Dictionary cites Thoreau as an authority for words and meanings more than 600 times, but not for a new science. But in effect, and without intending it, Thoreau has become one of the giants of the science of phenology, a word not recorded in use until 1884.

Phenology is the study of when natural events happen; when buds burst, flowers bloom, birds nest, insects pupate, fruit falls and leaves drop.

Thoreau, first to use the imagery of those who march to a different beat (he wrote: “If a man does not keep pace with his companions, perhaps it is because he hears a different drummer”), has already been cited as a phenological authority.

More than five years ago scientists used his nature notes to confirm that woody plants around Walden Pond were leafing up to 18 days earlier, thanks to climate change driven by human use of fossil fuels that enrich the levels of atmospheric carbon dioxide and warm the world. Temperatures on average around Concord, Massachusetts have risen by around 3°C since Thoreau vacated his cabin at nearby Walden.

“Our changing climate is affecting native wildflowers beloved by so many people”

If spring happens earlier for the trees of the canopy than it does for the shrubs of the understorey, then the wildflowers have less time for photosynthesis and are placed at a disadvantage in the competition for growth.

The evidence seems to suggest that climate change could already be limiting wildflower abundance: if fewer blooms ripen, there will be less seed for following years.

The asynchrony of leaf-out that could be changing the nature of Thoreau’s woods is likely to get more pronounced: by 2080, the northeastern US temperatures could have risen another 2.5 to 4.5°C.

It was Thoreau who memorably observed in one of his essays that “the mass of men lead lives of quiet desperation.” It could be even more desperate for his wildflowers. − Climate News Network

The writer’s notes left by the US thinker and naturalist known as the sage of Walden Pond have yielded more evidence of climate change.

LONDON, 27 March, 2019 − Henry David Thoreau, author of the memoir Walden, or Life in the Woods, in 1854, did more than just observe the oaks, the aspens, the “golden-rods, pinweeds and graceful wild grasses”: he left precise writer’s notes on the natural world he found during his wilful exile in the Massachusetts wilderness.

And thanks to these, US researchers now know that as the world warms, the native ecosystem that Thoreau observed and recorded is out of step.

At the close of winter, the trees now leaf at least two weeks earlier. But the wildflowers that depend on their moment in the sun for a head start now form leaves only one week earlier.

Researchers from Tennessee, Massachusetts, Maine and New York State report in the journal Ecology Letters that they combined observations around Walden in 1852 with a sequence of observations made in 37 separate years up to 2018, and with separate field experiments in a Pennsylvania forest, to conclude that wildflowers could not keep pace

“Combining our work from Pittsburgh with Thoreau’s data revealed an overlooked yet critical implication of how our changing climate is affecting native wildflowers beloved by so many people,” said Mason Heberling, a botanist at the Carnegie Museum of Natural History in Pittsburgh, who led the research.

Novel science

The Oxford English Dictionary cites Thoreau as an authority for words and meanings more than 600 times, but not for a new science. But in effect, and without intending it, Thoreau has become one of the giants of the science of phenology, a word not recorded in use until 1884.

Phenology is the study of when natural events happen; when buds burst, flowers bloom, birds nest, insects pupate, fruit falls and leaves drop.

Thoreau, first to use the imagery of those who march to a different beat (he wrote: “If a man does not keep pace with his companions, perhaps it is because he hears a different drummer”), has already been cited as a phenological authority.

More than five years ago scientists used his nature notes to confirm that woody plants around Walden Pond were leafing up to 18 days earlier, thanks to climate change driven by human use of fossil fuels that enrich the levels of atmospheric carbon dioxide and warm the world. Temperatures on average around Concord, Massachusetts have risen by around 3°C since Thoreau vacated his cabin at nearby Walden.

“Our changing climate is affecting native wildflowers beloved by so many people”

If spring happens earlier for the trees of the canopy than it does for the shrubs of the understorey, then the wildflowers have less time for photosynthesis and are placed at a disadvantage in the competition for growth.

The evidence seems to suggest that climate change could already be limiting wildflower abundance: if fewer blooms ripen, there will be less seed for following years.

The asynchrony of leaf-out that could be changing the nature of Thoreau’s woods is likely to get more pronounced: by 2080, the northeastern US temperatures could have risen another 2.5 to 4.5°C.

It was Thoreau who memorably observed in one of his essays that “the mass of men lead lives of quiet desperation.” It could be even more desperate for his wildflowers. − Climate News Network

Gulf Stream slowdown may bring later cold

The Gulf Stream is weakening, and Europe could expect a prolonged cold spell as the world warms – but not the day after tomorrow.

LONDON, 25 March, 2019 – As the Gulf Stream weakens in a rapidly warming world, north-western Europe could paradoxically become cooler. There is, however, a time lag between those two climate change-related events, and US scientists now think they know how long that could be.
It could be as much as 400 years.

They know this because the world has warmed and cooled before, and as the difference between tropics and Arctic narrows, there is a change in the so-called Atlantic conveyor, an important part of the climate machine.

This vast Atlantic current carries a steady flow of warm water to the far north, making north-western Europe up to 5°C warmer than its latitude would otherwise dictate. Then, as it meets colder, denser Arctic waters, it dives, to carry its burden of surface carbon to the depths, and then flows southwards again.

This phenomenon, known as the Atlantic Meridional Overturning Circulation, or AMOC, is in effect Europe’s bespoke heating system: Britain’s chief scientific adviser once calculated that it delivers to the UK alone the warmth of 27,000 power stations.

“There are some precursors in the ocean, so we should be watching the ocean”

But evidence from climate history shows that this heating has been turned off a number of times. Europe was plunged into a cold snap 13,000 years ago during a period known as the Younger Dryas and then warmed up about 11,000 years ago.

New and sophisticated studies of fossil carbon show that anybody taking notes at the time might have observed the warning signs. About 400 years before the abrupt shift to a frosty spell, the Atlantic current weakened. And it started to strengthen again about four centuries before the world warmed.

The study, published in the journal Nature Communications, confirms what climate scientists have always known: any sudden catastrophic return of the Ice Ages – dramatised in Hollywood’s notorious 2004 climate change movie The Day After Tomorrow – won’t happen at action movie pace. But it will happen over decades, and now seemingly with several centuries of advance notice.

“Our reconstructions indicate that there are clear climate precursors provided by the ocean state – like warning signs, so to speak,” said Francesco Muschitiello, then of the Lamont-Doherty Earth Observatory at Columbia University, US, and now at the University of Cambridge in the UK, who led the research.

Timing established

Climate scientists have clear dates for the timing of the Younger Dryas event: ice cores from the Arctic show both that Greenland’s temperature fell by 6°C or more at the beginning of the cycle, and that it rose by at least 8°C at its end.

To time the changes in the ocean current, they used carbon-dating techniques to identify a pattern of change in the marine sediments in the Norwegian Sea.

Since marine sediments settle very slowly, over very long periods of time, they needed a more precise “clock” to help calibrate their calculations: they found this in the fossilised ancient plants in a Scandinavian lake.

The isotope carbon-14 is pulled directly from the atmosphere each season by growing foliage. It decays at a predictable rate, and the amount of surviving C14 delivered a reliable clock. The identification of two volcanic ash layers from eruptions in Iceland, in both lake and seabed, provided yet more confidence in the timings. From these factors, the researchers were able to identify a slowdown in the transport of carbon from surface to the deep – and thus a slowdown in the current.

Long wait

The research confirms a link between ocean circulation patterns and northern hemisphere climate shifts: it provides evidence of what could be a considerable interval between the two.

Researchers have repeatedly warned that the Atlantic current seemed to be slowing, in response to global warming driven by profligate fossil fuel use by humankind, and that the consequences of continued slowdown could be very uncomfortable for hundreds of millions.

If the evidence from the Younger Dryas provides a sure parallel to today’s conditions, then Europeans might have time to prepare.

“It is clear that there are some precursors in the ocean, so we should be watching the ocean,” said Dr Muschitiello. “The mere fact that AMOC has been slowing down, that should be a concern based on what we have found.” – Climate News Network

The Gulf Stream is weakening, and Europe could expect a prolonged cold spell as the world warms – but not the day after tomorrow.

LONDON, 25 March, 2019 – As the Gulf Stream weakens in a rapidly warming world, north-western Europe could paradoxically become cooler. There is, however, a time lag between those two climate change-related events, and US scientists now think they know how long that could be.
It could be as much as 400 years.

They know this because the world has warmed and cooled before, and as the difference between tropics and Arctic narrows, there is a change in the so-called Atlantic conveyor, an important part of the climate machine.

This vast Atlantic current carries a steady flow of warm water to the far north, making north-western Europe up to 5°C warmer than its latitude would otherwise dictate. Then, as it meets colder, denser Arctic waters, it dives, to carry its burden of surface carbon to the depths, and then flows southwards again.

This phenomenon, known as the Atlantic Meridional Overturning Circulation, or AMOC, is in effect Europe’s bespoke heating system: Britain’s chief scientific adviser once calculated that it delivers to the UK alone the warmth of 27,000 power stations.

“There are some precursors in the ocean, so we should be watching the ocean”

But evidence from climate history shows that this heating has been turned off a number of times. Europe was plunged into a cold snap 13,000 years ago during a period known as the Younger Dryas and then warmed up about 11,000 years ago.

New and sophisticated studies of fossil carbon show that anybody taking notes at the time might have observed the warning signs. About 400 years before the abrupt shift to a frosty spell, the Atlantic current weakened. And it started to strengthen again about four centuries before the world warmed.

The study, published in the journal Nature Communications, confirms what climate scientists have always known: any sudden catastrophic return of the Ice Ages – dramatised in Hollywood’s notorious 2004 climate change movie The Day After Tomorrow – won’t happen at action movie pace. But it will happen over decades, and now seemingly with several centuries of advance notice.

“Our reconstructions indicate that there are clear climate precursors provided by the ocean state – like warning signs, so to speak,” said Francesco Muschitiello, then of the Lamont-Doherty Earth Observatory at Columbia University, US, and now at the University of Cambridge in the UK, who led the research.

Timing established

Climate scientists have clear dates for the timing of the Younger Dryas event: ice cores from the Arctic show both that Greenland’s temperature fell by 6°C or more at the beginning of the cycle, and that it rose by at least 8°C at its end.

To time the changes in the ocean current, they used carbon-dating techniques to identify a pattern of change in the marine sediments in the Norwegian Sea.

Since marine sediments settle very slowly, over very long periods of time, they needed a more precise “clock” to help calibrate their calculations: they found this in the fossilised ancient plants in a Scandinavian lake.

The isotope carbon-14 is pulled directly from the atmosphere each season by growing foliage. It decays at a predictable rate, and the amount of surviving C14 delivered a reliable clock. The identification of two volcanic ash layers from eruptions in Iceland, in both lake and seabed, provided yet more confidence in the timings. From these factors, the researchers were able to identify a slowdown in the transport of carbon from surface to the deep – and thus a slowdown in the current.

Long wait

The research confirms a link between ocean circulation patterns and northern hemisphere climate shifts: it provides evidence of what could be a considerable interval between the two.

Researchers have repeatedly warned that the Atlantic current seemed to be slowing, in response to global warming driven by profligate fossil fuel use by humankind, and that the consequences of continued slowdown could be very uncomfortable for hundreds of millions.

If the evidence from the Younger Dryas provides a sure parallel to today’s conditions, then Europeans might have time to prepare.

“It is clear that there are some precursors in the ocean, so we should be watching the ocean,” said Dr Muschitiello. “The mere fact that AMOC has been slowing down, that should be a concern based on what we have found.” – Climate News Network

Oceanic carbon uptake could falter

What does oceanic carbon uptake achieve? Greenhouse gas that sinks below the waves slows global warming a little and makes the water more acidic.

LONDON, 20 March, 2019 − Scientists can now put a measure to the role of the waves as a climate shock absorber: they estimate that oceanic carbon uptake by the deep blue seas has consumed 34 billion tonnes of man-made carbon from the atmosphere between the years 1994 and 2007.

This is just about 31% of all the carbon emitted in that time by car exhausts, power station chimneys, aircraft, ships, tractors and scorched forest, as human economies expand and ever more fossil fuel is consumed.

This confident figure is based on a global survey of the chemistry and other physical properties of the ocean by scientists from seven nations on more than 50 research cruises, taking measurements of the ocean from the surface to a depth of six kilometres.

The researchers report in the journal Science that they already had the results of a global carbon survey of the oceans conducted at the close of the last century, and had calculated that from the dawn of the Industrial Revolution – when humans started using coal, and then oil and gas – to 1994, the oceans had already absorbed 118 billion tonnes.

“The marine sink does not just respond to the increase in atmospheric CO2. Its substantial sensitivity to climate variations suggests a significant potential for feedbacks”

For the latest exercise, they developed a statistical tool that helped them make the distinction between the man-made and the natural atmospheric carbon dioxide always found dissolved in water.

The good news is that the ocean remains for the moment a stable component of the planet’s carbon budget: overall, as more man-made carbon is emitted from exhausts and chimneys, the ocean takes up proportionally more.

The bad news is that this may not go on for ever. At some point, the planet’s seas could become saturated with carbon, leaving ever more in the atmosphere to accelerate global warming to ever more alarming temperatures.

And there is a second unhappy consequence: the more carbon dioxide absorbed by the oceans, the more the sea shifts towards a weak solution of carbonic acid, with potentially calamitous consequences both for marine life and for commercial fisheries.

Research like this is essentially of academic interest: it adds precision to the big picture of a vast ocean that absorbs carbon dioxide, and overturning currents that take it to great depths, and out of atmospheric circulation.

An active moderator

But it is also a reminder that the ocean plays an active role in moderating planetary temperatures, absorbing ever greater quantities of heat and responding with fiercer levels of energy.

It also confirms that although, on average, the high seas are responding to atmospheric change as expected, different ocean basins can vary: the North Atlantic actually absorbed 20% less CO2 than expected between 1994 and 2007, probably thanks to the slowing of the North Atlantic Meridional Overturning Circulation at the time.

And, the researchers say, the acidification of the oceans is on the increase, to depths of 3000 metres. The next step is to understand a little better the interplay between ocean, atmosphere and human emissions of greenhouse gases.

“We learned that the marine sink does not just respond to the increase in atmospheric CO2,” said Nicolas Gruber of the Swiss Federal Institute of Technology, always known as ETH Zurich, who led the study.

“Its substantial sensitivity to climate variations suggests a significant potential for feedbacks with the ongoing change in climate.” − Climate News Network

What does oceanic carbon uptake achieve? Greenhouse gas that sinks below the waves slows global warming a little and makes the water more acidic.

LONDON, 20 March, 2019 − Scientists can now put a measure to the role of the waves as a climate shock absorber: they estimate that oceanic carbon uptake by the deep blue seas has consumed 34 billion tonnes of man-made carbon from the atmosphere between the years 1994 and 2007.

This is just about 31% of all the carbon emitted in that time by car exhausts, power station chimneys, aircraft, ships, tractors and scorched forest, as human economies expand and ever more fossil fuel is consumed.

This confident figure is based on a global survey of the chemistry and other physical properties of the ocean by scientists from seven nations on more than 50 research cruises, taking measurements of the ocean from the surface to a depth of six kilometres.

The researchers report in the journal Science that they already had the results of a global carbon survey of the oceans conducted at the close of the last century, and had calculated that from the dawn of the Industrial Revolution – when humans started using coal, and then oil and gas – to 1994, the oceans had already absorbed 118 billion tonnes.

“The marine sink does not just respond to the increase in atmospheric CO2. Its substantial sensitivity to climate variations suggests a significant potential for feedbacks”

For the latest exercise, they developed a statistical tool that helped them make the distinction between the man-made and the natural atmospheric carbon dioxide always found dissolved in water.

The good news is that the ocean remains for the moment a stable component of the planet’s carbon budget: overall, as more man-made carbon is emitted from exhausts and chimneys, the ocean takes up proportionally more.

The bad news is that this may not go on for ever. At some point, the planet’s seas could become saturated with carbon, leaving ever more in the atmosphere to accelerate global warming to ever more alarming temperatures.

And there is a second unhappy consequence: the more carbon dioxide absorbed by the oceans, the more the sea shifts towards a weak solution of carbonic acid, with potentially calamitous consequences both for marine life and for commercial fisheries.

Research like this is essentially of academic interest: it adds precision to the big picture of a vast ocean that absorbs carbon dioxide, and overturning currents that take it to great depths, and out of atmospheric circulation.

An active moderator

But it is also a reminder that the ocean plays an active role in moderating planetary temperatures, absorbing ever greater quantities of heat and responding with fiercer levels of energy.

It also confirms that although, on average, the high seas are responding to atmospheric change as expected, different ocean basins can vary: the North Atlantic actually absorbed 20% less CO2 than expected between 1994 and 2007, probably thanks to the slowing of the North Atlantic Meridional Overturning Circulation at the time.

And, the researchers say, the acidification of the oceans is on the increase, to depths of 3000 metres. The next step is to understand a little better the interplay between ocean, atmosphere and human emissions of greenhouse gases.

“We learned that the marine sink does not just respond to the increase in atmospheric CO2,” said Nicolas Gruber of the Swiss Federal Institute of Technology, always known as ETH Zurich, who led the study.

“Its substantial sensitivity to climate variations suggests a significant potential for feedbacks with the ongoing change in climate.” − Climate News Network

More acidic seas devour marine food web

As more acidic seas spread across the globe, conditions for survival start to change. That could close vast volumes of ocean for vital forms of life.

LONDON, 13 March, 2019 – By the close of the century, parts of the Southern Ocean could become impoverished as more acidic seas displace abundant marine food resources. Tiny sea snails that form the basis of the food supply for one of the world’s richest ecosystems could disappear because the depth at which they can form their shells will have shifted.

Right now, in Antarctic waters, creatures known as pteropods can exploit the calcium carbonate dissolved in the oceans down to a depth of 1000 metres to grow their shells.

But as atmospheric carbon dioxide levels soar, as a consequence of profligate use of fossil fuels by humankind, the chemistry of the oceans will shift towards the acidic.

The ratios of two kinds of carbonate – calcite and aragonite – will alter. And by 2100, there won’t be enough aragonite.

“A pocket of corrosive water will sit just below the surface, making life difficult for these communities of primarily surface-dwelling organisms”

Right now, pteropods flourish in the top 300 metres of the ocean. By 2100, the survival zone for the pteropods will end at a depth of 83 metres.

And, scientists warn in the journal Nature Climate Change, this could “change food web dynamics and have cascading effects on global ocean ecosystems.” In other words, the larger fish and marine mammals that feed on the smaller creatures that in turn depend on a basic diet of pteropods will have nothing to eat.

And that can only be bad news for global fisheries.

All shelled marine creatures – the tiny coccolithophores that die and leave their shells as chalk, the clams and molluscs, the foraminifera that float on the surface or coat the rocks and the seafloor, and the corals that are the basis for rich tropical ecosystems, all depend on the right levels of calcite and aragonite to form their exoskeletons.

The oceans are the biggest living space on the planet: the waves cover 70% of all living space and the depth of the deepest trenches is far greater than the highest terrestrial mountain ranges.

Origin of life

The oceans are the crucible in which life first emerged, and the oceans ultimately provided the sediments from which humankind has built its cities.

US and Norwegian scientists chose one species with precise needs in one reach of ocean as an indicator or what climate change driven by ever greater levels of the greenhouse gas carbon dioxide could do to an ocean ecosystem.

They found that what they called the “aragonite saturation horizon” became dramatically shallower as the seas became more acidic.

“These calcifying organisms will struggle to build and maintain their shells as acidification proceeds,” said Nicole Lovenduski, of the University of Colorado at Boulder, one of the researchers.

Inevitable result

“In the future, a pocket of corrosive water will sit just below the surface, making life difficult for these communities of primarily surface-dwelling organisms.”

As the world warms, acidification of the oceans becomes inevitable. Researchers have repeatedly warned that such change can only diminish ocean life, harm the coral reefs and kelp forests that shelter the rich biodiversity of sea creatures, change the behaviour of fish and some kinds of shrimp and threaten the shellfish harvest.

But for the first time, scientists have been able to model the impact of atmospheric change on the ocean chemistry in one zone at precise depths. The message is that right now, the pteropods have plenty of sea space for survival. But the aragonite saturation horizon may have already begun to shift in some places: perhaps as early as 2006, or as late as 2038. Once change begins, it will continue.

“If emissions were curbed tomorrow, this suddenly shallow horizon would still appear, even if possibly delayed,” said Dr Lovenduski. “And that, inevitably, along with lack of time for organisms to adapt, is most concerning.” – Climate News Network

As more acidic seas spread across the globe, conditions for survival start to change. That could close vast volumes of ocean for vital forms of life.

LONDON, 13 March, 2019 – By the close of the century, parts of the Southern Ocean could become impoverished as more acidic seas displace abundant marine food resources. Tiny sea snails that form the basis of the food supply for one of the world’s richest ecosystems could disappear because the depth at which they can form their shells will have shifted.

Right now, in Antarctic waters, creatures known as pteropods can exploit the calcium carbonate dissolved in the oceans down to a depth of 1000 metres to grow their shells.

But as atmospheric carbon dioxide levels soar, as a consequence of profligate use of fossil fuels by humankind, the chemistry of the oceans will shift towards the acidic.

The ratios of two kinds of carbonate – calcite and aragonite – will alter. And by 2100, there won’t be enough aragonite.

“A pocket of corrosive water will sit just below the surface, making life difficult for these communities of primarily surface-dwelling organisms”

Right now, pteropods flourish in the top 300 metres of the ocean. By 2100, the survival zone for the pteropods will end at a depth of 83 metres.

And, scientists warn in the journal Nature Climate Change, this could “change food web dynamics and have cascading effects on global ocean ecosystems.” In other words, the larger fish and marine mammals that feed on the smaller creatures that in turn depend on a basic diet of pteropods will have nothing to eat.

And that can only be bad news for global fisheries.

All shelled marine creatures – the tiny coccolithophores that die and leave their shells as chalk, the clams and molluscs, the foraminifera that float on the surface or coat the rocks and the seafloor, and the corals that are the basis for rich tropical ecosystems, all depend on the right levels of calcite and aragonite to form their exoskeletons.

The oceans are the biggest living space on the planet: the waves cover 70% of all living space and the depth of the deepest trenches is far greater than the highest terrestrial mountain ranges.

Origin of life

The oceans are the crucible in which life first emerged, and the oceans ultimately provided the sediments from which humankind has built its cities.

US and Norwegian scientists chose one species with precise needs in one reach of ocean as an indicator or what climate change driven by ever greater levels of the greenhouse gas carbon dioxide could do to an ocean ecosystem.

They found that what they called the “aragonite saturation horizon” became dramatically shallower as the seas became more acidic.

“These calcifying organisms will struggle to build and maintain their shells as acidification proceeds,” said Nicole Lovenduski, of the University of Colorado at Boulder, one of the researchers.

Inevitable result

“In the future, a pocket of corrosive water will sit just below the surface, making life difficult for these communities of primarily surface-dwelling organisms.”

As the world warms, acidification of the oceans becomes inevitable. Researchers have repeatedly warned that such change can only diminish ocean life, harm the coral reefs and kelp forests that shelter the rich biodiversity of sea creatures, change the behaviour of fish and some kinds of shrimp and threaten the shellfish harvest.

But for the first time, scientists have been able to model the impact of atmospheric change on the ocean chemistry in one zone at precise depths. The message is that right now, the pteropods have plenty of sea space for survival. But the aragonite saturation horizon may have already begun to shift in some places: perhaps as early as 2006, or as late as 2038. Once change begins, it will continue.

“If emissions were curbed tomorrow, this suddenly shallow horizon would still appear, even if possibly delayed,” said Dr Lovenduski. “And that, inevitably, along with lack of time for organisms to adapt, is most concerning.” – Climate News Network