Tag Archives: Carbon budget

Seas and forests are muddying the carbon budget

As climates change, forests may not absorb more carbon as expected. But a new carbon budget could appeal to the oceans.

LONDON, 18 September 2020 – Two new studies could throw long-term climate forecasts into confusion. The planetary carbon budget – the all-important traffic of life’s first element between rocks, water, atmosphere and living things – that underpins planetary temperatures and maintains a stable climate needs a rethink.

A warming climate makes trees grow faster. The awkward finding is that  faster-growing trees die younger. Therefore they must surrender their carbon back to the atmosphere quicker.

So tomorrow’s forests may not be quite such reliable long-term banks of carbon pumped into the atmosphere as a consequence of profligate fossil fuel use by human economies.

The more reassuring news is that the ocean – that’s almost three fourths of the planet’s surface – may absorb and store a lot more atmospheric carbon than previous estimates suggest.

All calculations about the future rate of global heating, and the potential consequences of climate change, rest upon the carbon budget.

Forest doubts

This is the intricate accounting of the mass of carbon in continuous circulation from air to plant to animal and then to shell, skeleton and sediment, and the expected flow of carbon emissions from the combustion of fossil fuels stored hundreds of millions of years ago, and exhumed in the last two centuries.

To make sense of the factors at work, climate scientists have to make calculations about all the carbon stored in the permafrost, in the soils, in the forests, dissolved in the oceans, free in the atmosphere and being released from power station chimneys, vehicle exhausts and ploughed or scorched land.

But for decades, one component of the equation has been automatically accepted: more forests must mean more carbon absorbed, and better protected natural forests would store the most carbon, the most efficiently.

Now a new report in the journal Nature Communications introduces some doubt into this cornerstone of the carbon budget. In an already warming world, much more of the carbon stored in tomorrow’s forests might find its way back into the atmosphere.

Researchers looked at 200,000 tree ring records from 82 tree species from sites around the planet. They found what they describe as trade-offs that are near universal: faster-growing trees have shorter lives.

“There is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality”

This was true in cool climates and warm ones, and in all species. So the hope that natural vegetation will respond to warmer temperatures by absorbing even more carbon becomes insecure, especially if it means that the more vigorous growth means simply swifter death and decay.

“Our modeling suggests that there is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality,” said Roel Brienen of the University of Leeds in the UK, who led the research. “They estimate that global increases in tree death don’t kick in until after sites show accelerated growth.”

All such research is provisional: the findings gain currency only when supported by other teams using different approaches. So it has yet to be confirmed.

But recent studies have suggested that climate change has already begun to complicate calculations. Just in recent months, research teams have found that forest trees are growing shorter and dying younger; that higher temperatures may affect plant germination; and that forests already hit by drought may start surrendering carbon more swiftly than they absorb it. Planting more trees is not an alternative to reducing greenhouse gas emissions.

On the other hand, the carbon budget may still make sense: the oceans may be responding to ever-higher concentrations of carbon dioxide by absorbing more from the atmosphere, which also makes the oceans more acidic, which is not necessarily helpful.

Oceans’ effect

All such calculations are based on sea surface temperatures. Gases such as carbon dioxide and oxygen dissolve well in colder water, not so well in warm lagoons and tropical tides.

But a British group reports in the same journal that calculations so far may have been under-estimates. This is because, on balance, researchers have tended to ignore the small difference between the temperatures at the surface, and a few metres down, where the measurements of dissolved greenhouse gas were actually made.

A team from the University of Exeter worked from a global database to make new estimates of the oceans’ appetite for carbon between 1992 and 2018.

“We used satellite data to correct for these temperature differences, and when we do that, it makes a big difference – we get a substantially larger flux going into the ocean,” said Andrew Watson, who led the study.

“The difference in ocean uptake we calculate amounts to 10% of global fossil fuel emissions.” – Climate News Network

As climates change, forests may not absorb more carbon as expected. But a new carbon budget could appeal to the oceans.

LONDON, 18 September 2020 – Two new studies could throw long-term climate forecasts into confusion. The planetary carbon budget – the all-important traffic of life’s first element between rocks, water, atmosphere and living things – that underpins planetary temperatures and maintains a stable climate needs a rethink.

A warming climate makes trees grow faster. The awkward finding is that  faster-growing trees die younger. Therefore they must surrender their carbon back to the atmosphere quicker.

So tomorrow’s forests may not be quite such reliable long-term banks of carbon pumped into the atmosphere as a consequence of profligate fossil fuel use by human economies.

The more reassuring news is that the ocean – that’s almost three fourths of the planet’s surface – may absorb and store a lot more atmospheric carbon than previous estimates suggest.

All calculations about the future rate of global heating, and the potential consequences of climate change, rest upon the carbon budget.

Forest doubts

This is the intricate accounting of the mass of carbon in continuous circulation from air to plant to animal and then to shell, skeleton and sediment, and the expected flow of carbon emissions from the combustion of fossil fuels stored hundreds of millions of years ago, and exhumed in the last two centuries.

To make sense of the factors at work, climate scientists have to make calculations about all the carbon stored in the permafrost, in the soils, in the forests, dissolved in the oceans, free in the atmosphere and being released from power station chimneys, vehicle exhausts and ploughed or scorched land.

But for decades, one component of the equation has been automatically accepted: more forests must mean more carbon absorbed, and better protected natural forests would store the most carbon, the most efficiently.

Now a new report in the journal Nature Communications introduces some doubt into this cornerstone of the carbon budget. In an already warming world, much more of the carbon stored in tomorrow’s forests might find its way back into the atmosphere.

Researchers looked at 200,000 tree ring records from 82 tree species from sites around the planet. They found what they describe as trade-offs that are near universal: faster-growing trees have shorter lives.

“There is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality”

This was true in cool climates and warm ones, and in all species. So the hope that natural vegetation will respond to warmer temperatures by absorbing even more carbon becomes insecure, especially if it means that the more vigorous growth means simply swifter death and decay.

“Our modeling suggests that there is likely to be a timelag before we see the worst of the potential loss of carbon stocks from increases in tree mortality,” said Roel Brienen of the University of Leeds in the UK, who led the research. “They estimate that global increases in tree death don’t kick in until after sites show accelerated growth.”

All such research is provisional: the findings gain currency only when supported by other teams using different approaches. So it has yet to be confirmed.

But recent studies have suggested that climate change has already begun to complicate calculations. Just in recent months, research teams have found that forest trees are growing shorter and dying younger; that higher temperatures may affect plant germination; and that forests already hit by drought may start surrendering carbon more swiftly than they absorb it. Planting more trees is not an alternative to reducing greenhouse gas emissions.

On the other hand, the carbon budget may still make sense: the oceans may be responding to ever-higher concentrations of carbon dioxide by absorbing more from the atmosphere, which also makes the oceans more acidic, which is not necessarily helpful.

Oceans’ effect

All such calculations are based on sea surface temperatures. Gases such as carbon dioxide and oxygen dissolve well in colder water, not so well in warm lagoons and tropical tides.

But a British group reports in the same journal that calculations so far may have been under-estimates. This is because, on balance, researchers have tended to ignore the small difference between the temperatures at the surface, and a few metres down, where the measurements of dissolved greenhouse gas were actually made.

A team from the University of Exeter worked from a global database to make new estimates of the oceans’ appetite for carbon between 1992 and 2018.

“We used satellite data to correct for these temperature differences, and when we do that, it makes a big difference – we get a substantially larger flux going into the ocean,” said Andrew Watson, who led the study.

“The difference in ocean uptake we calculate amounts to 10% of global fossil fuel emissions.” – Climate News Network

The carbon budget doesn't add up

FOR IMMEDIATE RELEASE
The IPCC’s report on the state of the climate spells out for the first time how much of the greenhouse gases available to humanity we can afford to burn. The answer is not good news.

LONDON, 1 October – Amid the swirling cross-currents of praise and damnation which greeted last week’s publication of the Intergovernmental Panel on Climate Change’s Fifth Assessment Report (AR5), one key finding has attracted fewer headlines than it deserved.

The authors of AR5 said the world had already used between half and two-thirds of its “carbon budget” – the amount of carbon dioxide it can afford to burn this century without pushing us over the edge to a planet more than 2°C warmer than in the pre-industrial era.

The 2°C threshold is a limit agreed by most of the world’s governments as a safety point beyond which global warming could lurch uncontrollably towards a possibly irreversible catastrophe for modern society.

It is not a scientifically-validated figure, and many climate scientists argue that it would make better sense to stop warming increasing above 1.5°C. But at least the 2°C limit has wide political acceptance – in principle.

In practice, though, emissions of all greenhouse gases continue to rise, with little prospect that they will start falling any time soon.

Su Wei is China’s chief climate change negotiator and director general of the department of climate change of its National Development and Reform Commission (NDRC).

Heading the wrong way

He said recently: “If we continue with business as usual, the long-term average temperature increase is more likely to be between 3.6°C and 5.3°C (compared with pre-industrial levels), with most of the increase occurring in this century.”

The IPCC has now set a total for the amount of CO2 and other greenhouse gases which it has concluded can safely be burnt during this century while offering at least a 50% chance of staying below the 2°C figure. The total is somewhere between 820 bn and 1,445 bn tonnes.

The quantity of greenhouse gases entering the atmosphere each year is now around 50 bn tonnes, so without sustained reductions there must be a fair chance – on present trends – of reaching the IPCC’s lower limit around 2030.

If emissions continue to rise, though, there will be less time left to ensure the world remains within the IPCC’s frame.

The introduction to one section of the IPCC’s Fourth Assessment Report, published in 2007, concluded that unless energy policies changed substantially the world would continue to depend on fossil fuels until 2025–2030, and that they would supply more than 80% of its energy.

Annual global energy-related CO2 emissions in 2030 were expected to be 40-110% higher than in 2000, with two-thirds of the increase originating in developing countries.

If there is any realistic possibility of stringent emissions cuts being first agreed and then implemented, one logical conclusion is that a large proportion of the world’s hitherto untapped coal, oil and gas reserves will have to remain underground, as exploiting them would simply produce wasted assets.

Renewables ‘are a better bet’

Lord Stern, the British academic who used to be the World Bank’s chief economist, says the IPCC’s carbon budget calculations must underlie the international climate negotiations.

These are due to resume in high gear next month in the Polish capital, Warsaw, and to conclude in Paris in 2015 with a new worldwide agreement on emissions cuts.

The Carbon Tracker Initiative aims to improve the transparency of the carbon embedded in equity markets by identifying the scale of unburnable carbon currently listed on the world’s stock exchanges in order to show the risk facing markets. It says renewable energy is a safer investment bet than “the unburnable carbon bubble”.

The Initiative’s chairman is Jeremy Leggett, who published a book last month, The Energy of Nations: Risk blindness and the road to renaissance.

He argues that fossil fuel and mining companies are greatly overvalued on the stock market, basing much of their worth on assets which should remain locked away where they are, safe below ground.

He may well be right. But it’s not an argument likely to appeal very strongly to states intent on buying cheap and available energy to lift their people out of poverty – nor to states anxious to sell hydrocarbons, either. Expect interesting times ahead. – Climate News Network

FOR IMMEDIATE RELEASE
The IPCC’s report on the state of the climate spells out for the first time how much of the greenhouse gases available to humanity we can afford to burn. The answer is not good news.

LONDON, 1 October – Amid the swirling cross-currents of praise and damnation which greeted last week’s publication of the Intergovernmental Panel on Climate Change’s Fifth Assessment Report (AR5), one key finding has attracted fewer headlines than it deserved.

The authors of AR5 said the world had already used between half and two-thirds of its “carbon budget” – the amount of carbon dioxide it can afford to burn this century without pushing us over the edge to a planet more than 2°C warmer than in the pre-industrial era.

The 2°C threshold is a limit agreed by most of the world’s governments as a safety point beyond which global warming could lurch uncontrollably towards a possibly irreversible catastrophe for modern society.

It is not a scientifically-validated figure, and many climate scientists argue that it would make better sense to stop warming increasing above 1.5°C. But at least the 2°C limit has wide political acceptance – in principle.

In practice, though, emissions of all greenhouse gases continue to rise, with little prospect that they will start falling any time soon.

Su Wei is China’s chief climate change negotiator and director general of the department of climate change of its National Development and Reform Commission (NDRC).

Heading the wrong way

He said recently: “If we continue with business as usual, the long-term average temperature increase is more likely to be between 3.6°C and 5.3°C (compared with pre-industrial levels), with most of the increase occurring in this century.”

The IPCC has now set a total for the amount of CO2 and other greenhouse gases which it has concluded can safely be burnt during this century while offering at least a 50% chance of staying below the 2°C figure. The total is somewhere between 820 bn and 1,445 bn tonnes.

The quantity of greenhouse gases entering the atmosphere each year is now around 50 bn tonnes, so without sustained reductions there must be a fair chance – on present trends – of reaching the IPCC’s lower limit around 2030.

If emissions continue to rise, though, there will be less time left to ensure the world remains within the IPCC’s frame.

The introduction to one section of the IPCC’s Fourth Assessment Report, published in 2007, concluded that unless energy policies changed substantially the world would continue to depend on fossil fuels until 2025–2030, and that they would supply more than 80% of its energy.

Annual global energy-related CO2 emissions in 2030 were expected to be 40-110% higher than in 2000, with two-thirds of the increase originating in developing countries.

If there is any realistic possibility of stringent emissions cuts being first agreed and then implemented, one logical conclusion is that a large proportion of the world’s hitherto untapped coal, oil and gas reserves will have to remain underground, as exploiting them would simply produce wasted assets.

Renewables ‘are a better bet’

Lord Stern, the British academic who used to be the World Bank’s chief economist, says the IPCC’s carbon budget calculations must underlie the international climate negotiations.

These are due to resume in high gear next month in the Polish capital, Warsaw, and to conclude in Paris in 2015 with a new worldwide agreement on emissions cuts.

The Carbon Tracker Initiative aims to improve the transparency of the carbon embedded in equity markets by identifying the scale of unburnable carbon currently listed on the world’s stock exchanges in order to show the risk facing markets. It says renewable energy is a safer investment bet than “the unburnable carbon bubble”.

The Initiative’s chairman is Jeremy Leggett, who published a book last month, The Energy of Nations: Risk blindness and the road to renaissance.

He argues that fossil fuel and mining companies are greatly overvalued on the stock market, basing much of their worth on assets which should remain locked away where they are, safe below ground.

He may well be right. But it’s not an argument likely to appeal very strongly to states intent on buying cheap and available energy to lift their people out of poverty – nor to states anxious to sell hydrocarbons, either. Expect interesting times ahead. – Climate News Network

The carbon budget doesn’t add up

FOR IMMEDIATE RELEASE The IPCC’s report on the state of the climate spells out for the first time how much of the greenhouse gases available to humanity we can afford to burn. The answer is not good news. LONDON, 1 October – Amid the swirling cross-currents of praise and damnation which greeted last week’s publication of the Intergovernmental Panel on Climate Change’s Fifth Assessment Report (AR5), one key finding has attracted fewer headlines than it deserved. The authors of AR5 said the world had already used between half and two-thirds of its “carbon budget” – the amount of carbon dioxide it can afford to burn this century without pushing us over the edge to a planet more than 2°C warmer than in the pre-industrial era. The 2°C threshold is a limit agreed by most of the world’s governments as a safety point beyond which global warming could lurch uncontrollably towards a possibly irreversible catastrophe for modern society. It is not a scientifically-validated figure, and many climate scientists argue that it would make better sense to stop warming increasing above 1.5°C. But at least the 2°C limit has wide political acceptance – in principle. In practice, though, emissions of all greenhouse gases continue to rise, with little prospect that they will start falling any time soon. Su Wei is China’s chief climate change negotiator and director general of the department of climate change of its National Development and Reform Commission (NDRC).

Heading the wrong way

He said recently: “If we continue with business as usual, the long-term average temperature increase is more likely to be between 3.6°C and 5.3°C (compared with pre-industrial levels), with most of the increase occurring in this century.” The IPCC has now set a total for the amount of CO2 and other greenhouse gases which it has concluded can safely be burnt during this century while offering at least a 50% chance of staying below the 2°C figure. The total is somewhere between 820 bn and 1,445 bn tonnes. The quantity of greenhouse gases entering the atmosphere each year is now around 50 bn tonnes, so without sustained reductions there must be a fair chance – on present trends – of reaching the IPCC’s lower limit around 2030. If emissions continue to rise, though, there will be less time left to ensure the world remains within the IPCC’s frame. The introduction to one section of the IPCC’s Fourth Assessment Report, published in 2007, concluded that unless energy policies changed substantially the world would continue to depend on fossil fuels until 2025–2030, and that they would supply more than 80% of its energy. Annual global energy-related CO2 emissions in 2030 were expected to be 40-110% higher than in 2000, with two-thirds of the increase originating in developing countries. If there is any realistic possibility of stringent emissions cuts being first agreed and then implemented, one logical conclusion is that a large proportion of the world’s hitherto untapped coal, oil and gas reserves will have to remain underground, as exploiting them would simply produce wasted assets.

Renewables ‘are a better bet’

Lord Stern, the British academic who used to be the World Bank’s chief economist, says the IPCC’s carbon budget calculations must underlie the international climate negotiations. These are due to resume in high gear next month in the Polish capital, Warsaw, and to conclude in Paris in 2015 with a new worldwide agreement on emissions cuts. The Carbon Tracker Initiative aims to improve the transparency of the carbon embedded in equity markets by identifying the scale of unburnable carbon currently listed on the world’s stock exchanges in order to show the risk facing markets. It says renewable energy is a safer investment bet than “the unburnable carbon bubble”. The Initiative’s chairman is Jeremy Leggett, who published a book last month, The Energy of Nations: Risk blindness and the road to renaissance. He argues that fossil fuel and mining companies are greatly overvalued on the stock market, basing much of their worth on assets which should remain locked away where they are, safe below ground. He may well be right. But it’s not an argument likely to appeal very strongly to states intent on buying cheap and available energy to lift their people out of poverty – nor to states anxious to sell hydrocarbons, either. Expect interesting times ahead. – Climate News Network

FOR IMMEDIATE RELEASE The IPCC’s report on the state of the climate spells out for the first time how much of the greenhouse gases available to humanity we can afford to burn. The answer is not good news. LONDON, 1 October – Amid the swirling cross-currents of praise and damnation which greeted last week’s publication of the Intergovernmental Panel on Climate Change’s Fifth Assessment Report (AR5), one key finding has attracted fewer headlines than it deserved. The authors of AR5 said the world had already used between half and two-thirds of its “carbon budget” – the amount of carbon dioxide it can afford to burn this century without pushing us over the edge to a planet more than 2°C warmer than in the pre-industrial era. The 2°C threshold is a limit agreed by most of the world’s governments as a safety point beyond which global warming could lurch uncontrollably towards a possibly irreversible catastrophe for modern society. It is not a scientifically-validated figure, and many climate scientists argue that it would make better sense to stop warming increasing above 1.5°C. But at least the 2°C limit has wide political acceptance – in principle. In practice, though, emissions of all greenhouse gases continue to rise, with little prospect that they will start falling any time soon. Su Wei is China’s chief climate change negotiator and director general of the department of climate change of its National Development and Reform Commission (NDRC).

Heading the wrong way

He said recently: “If we continue with business as usual, the long-term average temperature increase is more likely to be between 3.6°C and 5.3°C (compared with pre-industrial levels), with most of the increase occurring in this century.” The IPCC has now set a total for the amount of CO2 and other greenhouse gases which it has concluded can safely be burnt during this century while offering at least a 50% chance of staying below the 2°C figure. The total is somewhere between 820 bn and 1,445 bn tonnes. The quantity of greenhouse gases entering the atmosphere each year is now around 50 bn tonnes, so without sustained reductions there must be a fair chance – on present trends – of reaching the IPCC’s lower limit around 2030. If emissions continue to rise, though, there will be less time left to ensure the world remains within the IPCC’s frame. The introduction to one section of the IPCC’s Fourth Assessment Report, published in 2007, concluded that unless energy policies changed substantially the world would continue to depend on fossil fuels until 2025–2030, and that they would supply more than 80% of its energy. Annual global energy-related CO2 emissions in 2030 were expected to be 40-110% higher than in 2000, with two-thirds of the increase originating in developing countries. If there is any realistic possibility of stringent emissions cuts being first agreed and then implemented, one logical conclusion is that a large proportion of the world’s hitherto untapped coal, oil and gas reserves will have to remain underground, as exploiting them would simply produce wasted assets.

Renewables ‘are a better bet’

Lord Stern, the British academic who used to be the World Bank’s chief economist, says the IPCC’s carbon budget calculations must underlie the international climate negotiations. These are due to resume in high gear next month in the Polish capital, Warsaw, and to conclude in Paris in 2015 with a new worldwide agreement on emissions cuts. The Carbon Tracker Initiative aims to improve the transparency of the carbon embedded in equity markets by identifying the scale of unburnable carbon currently listed on the world’s stock exchanges in order to show the risk facing markets. It says renewable energy is a safer investment bet than “the unburnable carbon bubble”. The Initiative’s chairman is Jeremy Leggett, who published a book last month, The Energy of Nations: Risk blindness and the road to renaissance. He argues that fossil fuel and mining companies are greatly overvalued on the stock market, basing much of their worth on assets which should remain locked away where they are, safe below ground. He may well be right. But it’s not an argument likely to appeal very strongly to states intent on buying cheap and available energy to lift their people out of poverty – nor to states anxious to sell hydrocarbons, either. Expect interesting times ahead. – Climate News Network