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New research suggests temperature and sea level rise could be far worse than climate models predict. (Photo: Christopher Michel/Flickr/cc)
Since the Intergovernmental Panel on Climate Change (IPCC) released its new, must-read report on the urgency of limiting global warming to 1.5 degrees Celsius, we at Oil Change International have been receiving some common questions: What are the implications for our analysis of what the Paris accord's goals mean for fossil fuel production? What about the IPCC's use of larger carbon budgets, compared to its last major report? What, if any, new conclusions do we draw?
The quick summary is this: It's clear that the IPCC's 1.5-degree report clarifies and adds urgency to our call for a managed decline of fossil fuel production. Winding down the largest source of carbon emissions--the oil, gas, and coal extracted by the fossil fuel industry--will be essential to achieving deep cuts in carbon emissions within the next decade, as the report warns is necessary. In this post, I'll unpack three key takeaways:
(Questions such as, Is there hope? (yes), and, Is this possible? (yes), are also critical parts of the discussion right now. I focus here the technical aspects related to our analysis.)
First, a bit of background: We at Oil Change International (OCI) first analyzed the limits that the Paris goals imply for fossil fuel production in 2016, and the results were sobering. In our report, The Sky's Limit: Why the Paris Goals Require a Managed Decline of Fossil Fuel Production, we found that the oil, gas, and coal in existing fields and mines globally contain enough potential carbon emissions to push the world beyond the Paris climate goals.
We arrived at this result by using carbon budgets from the IPCC's 5th Assessment Synthesis Report, which reflected the scientific consensus at the time. We took budgets that were consistent with the range of the Paris goals--aiming to limit warming to 1.5 degrees Celsius (degC) or "well below" 2degC. We then compared those budgets to the potential cumulative carbon dioxide (CO2) emissions from already-developed fossil fuel reserves globally. You can see the results in the figure below.
Developed Fossil Fuel Reserves, Compared to Carbon Budgets in the IPCC 5th Assessment Report [1]
We drew two primary conclusions from these results:
These recommendations were informed by our understanding of the dynamics of carbon lock-in. Developed reserves represent the oil, gas, and coal that the fossil fuel industry has already invested in extracting--the capital is sunk, the wells have been (or are being) drilled, the pits dug, and the related infrastructure constructed. Once a project is operating, there are economic, political, and legal factors that push for continued operation and present barriers to early closure.
Given the hard limit to how much fossil fuel can be extracted, and given the inertia behind existing projects, continuing to expand the footprint of the fossil fuel industry now risks two potentially overlapping outcomes: 1) Climate chaos, as the industry locks in levels of emissions that far exceed the Paris limits; and/or; 2) Economic chaos, from a sudden scramble to end fossil fuel production and use at a later date.
How has the new IPCC report adjusted our thinking?
The most important way the new IPCC has changed our thinking is that it has persuaded us that we need to aim to limit warming to 1.5 degrees, not just "well below 2 degrees." It's important to remember that 1.5degC exists as a goal within the Paris accord because some of the world's most climate-vulnerable nations demanded it, asserting this level of ambition as essential to their survival. The IPCC report provides powerful scientific backing for their call.
The report finds that exceeding 1.5degC of warming and hitting the 2degC threshold would put millions more people at risk of death, poverty, water and food shortages, and displacement from rising sea levels, while increasing the odds of irreversible, runaway ruptures in our climate system. We can significantly lessen the loss of human lives, whole communities, and ecosystems if governments interpret the upper limit of the Paris agreement--of keeping warming "well below" 2degC--to mean limiting it to 1.5degC.
Accordingly, we at OCI are shifting how we emphasize these goals in our own analysis, referring to 1.5degC first and as the primary aim when we discuss the Paris goals. We expect the IPCC report will encourage some governments and others to do the same.
One element of the new IPCC report has sparked questions and some confusion: the shifting size of the carbon budgets. As a basic concept, carbon budgets are relatively simple. They indicate how much CO2 can be emitted before the world reaches a certain temperature threshold. But calculating them depends on a variety of factors: how you measure the level of warming to date, how you measure temperatures (i.e., by air, sea, or a combination), how you define a "pre-industrial" baseline for human-caused emissions, exactly how many emissions have occurred since then, and how other greenhouse gas emissions influence the climate.
Since the IPCC's 5th Assessment Report, released in 2014, scientists have continued to examine the assumptions and methods that go into calculating carbon budgets. A much-debated paper released last year by Millar et al. (see our commentary on it here) proposed a new methodology, shifting the reference period from which models calculate carbon budgets to the recent past rather than pre-industrial times. Since the new reference period experienced slightly less warming than indicated by the models, the new methodology concluded that remaining carbon budgets for the 1.5degC and 2degC temperature thresholds may be larger as a result. The IPCC's 1.5-degree report adopted this new methodology, estimating that carbon budgets are roughly 300 gigatonnes (Gt) larger compared to those published in the 5th Assessment Report,[2] while noting that significant uncertainty remains around the size of this adjustment.
This is an active, ongoing scientific debate (for instructive overviews, read briefs from Climate Analytics and Carbon Brief). As such, it's not yet clear if the larger carbon budgets in the latest IPCC report fully reflect a new scientific consensus. In fact, it's so unsettled that the IPCC report gives two sets of budgets for each ambition level, based on different observational datasets. Some scientists have already said the report is too conservative, overstating remaining carbon budgets (in both versions) and understating risks. It's perhaps a case of unfortunate timing for the IPCC report, as it had to be written while that debate was just getting started.
Rather than waiting for a new consensus to be settled, let's take a look at what these larger budgets would mean if they're right. If we have a bit more space in global carbon budgets than previously thought, that's clearly a good thing. It would increase our chances of limiting catastrophic climate changes. Does this also imply there is some room to expand fossil fuel production?
The figure below shows how our original Sky's Limit calculation of developed fossil fuel reserves compares to the larger carbon budget sizes in the latest IPCC report (using the same 50 and 66 percent probability levels for 1.5degC and 2degC respectively). The bottom, darkest portions of the carbon budget bars show the budgets from the 5th Assessment Report (AR5), updated to reflect CO2 emissions through the end of 2017. The middle-shaded portions reflect the larger carbon budgets from the Special Report on 1.5 degrees (SR1.5) that use the same measure of warming as the 5th Assessment Report--global surface air temperature (GSAT). The top-shaded regions show the larger budgets based on a different temperature measure--global mean surface temperature (GMST), the average of air and sea surface temperatures.
For context, observational datasets generally use GMST, which is why the Millar et al. paper, based on observed warming to date, used them. On the other hand, the AR5, the scientific basis on which the Paris Agreement was reached, relied on GSAT. (For the sake of brevity, this is a simplification of the underlying science.) For assessing the Paris goals, one could argue against shifting goalposts. We look at both sets, since they both appear in the SR1.5.
Developed Fossil Fuel Reserves, Compared to Updated IPCC Carbon Budgets (GSAT and GMST) [3]
In each of these cases, developed reserves still significantly exceed the carbon budgets for a one-in-two chance of limiting warming to 1.5degC. Developed reserves are double the carbon budget for 1.5degC that's based on GSAT, after adding in optimistic estimates of future land use and cement manufacture emissions (which are more difficult to reduce than energy sector emissions).
With the larger budgets, there is some space between estimated emissions and the carbon budget limits for a two-in-three chance of staying with 2degC of warming (albeit just a sliver when looking at the Paris baseline of surface air temperature). If one sets aside the warnings of the IPCC report and accepts the upper limit of the Paris goals as written--keeping warming "well below" 2degC--one cannot reasonably interpret that bit of white space as a greenlight for new fossil fuel development. Rather, it offers a chance to manage the decline of fossil fuel extraction so that warming actually stays "well below"--rather than barely below--the 2-degree danger line.
Furthermore, given what the new report tells us about uncertainties in the budgets, a precautionary approach would imply aiming as low as possible. For example, the IPCC report authors caution, "Remaining budgets applicable to 2100, would approximately be 100 Gt CO2 lower...to account for permafrost thawing and potential methane release from wetlands in the future."
In short, while the larger budgets may give a welcome increase to our chance of success, there is still no room for new fossil fuel development.
The IPCC report makes clear that, irrespective of whether there is slightly more or less space in carbon budgets, there is no time to lose in rapidly reducing emissions. The report indicates that keeping warming within 1.5degC will require reducing carbon pollution by about 45 percent from 2010 levels by 2030 and reaching net zero emissions around 2050, as illustrated in the figure below from the report's Summary for Policymakers. Steering the world onto such a pathway will require"rapid and far-reaching" transitions and "deep emissions reductions in all sectors."
Global Total Net CO2 Emissions in Model Pathways Limiting Global Warming to 1.5degC
The report goes on to explain that the longer the world's countries delay in serious emissions cuts, the more they will be required to rely on so-called carbon dioxide removal (CDR) technologies in subsequent decades. The report also provides a warning of the ecological and social risks--and potential infeasibility--of this approach. "CDR deployed at scale is unproven and reliance on such technology is a major risk in the ability to limit warming to 1.5degC," the report states. This topic deserves its own dedicated blog post. For now, I'll leave it at this: Large-scale reliance on carbon dioxide removal technologies is, unsurprisingly, exactly what many fossil fuel companies point to in their own "climate" scenarios--because it would extend the lifetime of their fossil fuel business model.
Near-zero emissions by 2050 would mean close to zero fossil fuel extraction by 2050. If governments find the political will to heed the science and commit to a managed transition off of fossil fuel extraction, there will be a way. We have the clean technologies we need.
On the other hand, continuing to build out the fossil fuel economy risks putting the 1.5degC climate limit out of reach in the very-near future, and that would put millions of additional lives at risk. Rather than inviting climate and/or economic chaos, it's time for political leaders to plan seriously for climate success--to end the fossil fuel era in an equitable way.
Notes:
[1] Carbon budgets are taken from Table 2.2 of the AR5 Synthesis Report, and adjusted to remaining space from the start of 2018 (subtracting approximately 40 Gt CO2 per year for 2012-2017)
[2] See p. 16, footnote 14 of the SR1.5 Summary for Policymakers.
[3] The SR1.5 Summary for Policymakers cites the GSAT-based budget for a 50 percent chance at 1.5degC to be 580 Gt CO2 (see C1.3 on p. 16). The budgets using GSAT are in the process of being added to Chapter 2 of the SR1.5, and Table 2.2 in particular, to be consistent with the final Summary for Policymakers. The pending edits cite 1170 Gt CO2 as the GSAT-based budget for a 66 percent chance of limiting warming to 2degC. The GMST-based budgets for varying temperature limits and probabilities are found in the SR1.5 in Chapter 2, Table 2.2.
Trump and Musk are on an unconstitutional rampage, aiming for virtually every corner of the federal government. These two right-wing billionaires are targeting nurses, scientists, teachers, daycare providers, judges, veterans, air traffic controllers, and nuclear safety inspectors. No one is safe. The food stamps program, Social Security, Medicare, and Medicaid are next. It’s an unprecedented disaster and a five-alarm fire, but there will be a reckoning. The people did not vote for this. The American people do not want this dystopian hellscape that hides behind claims of “efficiency.” Still, in reality, it is all a giveaway to corporate interests and the libertarian dreams of far-right oligarchs like Musk. Common Dreams is playing a vital role by reporting day and night on this orgy of corruption and greed, as well as what everyday people can do to organize and fight back. As a people-powered nonprofit news outlet, we cover issues the corporate media never will, but we can only continue with our readers’ support. |
Since the Intergovernmental Panel on Climate Change (IPCC) released its new, must-read report on the urgency of limiting global warming to 1.5 degrees Celsius, we at Oil Change International have been receiving some common questions: What are the implications for our analysis of what the Paris accord's goals mean for fossil fuel production? What about the IPCC's use of larger carbon budgets, compared to its last major report? What, if any, new conclusions do we draw?
The quick summary is this: It's clear that the IPCC's 1.5-degree report clarifies and adds urgency to our call for a managed decline of fossil fuel production. Winding down the largest source of carbon emissions--the oil, gas, and coal extracted by the fossil fuel industry--will be essential to achieving deep cuts in carbon emissions within the next decade, as the report warns is necessary. In this post, I'll unpack three key takeaways:
(Questions such as, Is there hope? (yes), and, Is this possible? (yes), are also critical parts of the discussion right now. I focus here the technical aspects related to our analysis.)
First, a bit of background: We at Oil Change International (OCI) first analyzed the limits that the Paris goals imply for fossil fuel production in 2016, and the results were sobering. In our report, The Sky's Limit: Why the Paris Goals Require a Managed Decline of Fossil Fuel Production, we found that the oil, gas, and coal in existing fields and mines globally contain enough potential carbon emissions to push the world beyond the Paris climate goals.
We arrived at this result by using carbon budgets from the IPCC's 5th Assessment Synthesis Report, which reflected the scientific consensus at the time. We took budgets that were consistent with the range of the Paris goals--aiming to limit warming to 1.5 degrees Celsius (degC) or "well below" 2degC. We then compared those budgets to the potential cumulative carbon dioxide (CO2) emissions from already-developed fossil fuel reserves globally. You can see the results in the figure below.
Developed Fossil Fuel Reserves, Compared to Carbon Budgets in the IPCC 5th Assessment Report [1]
We drew two primary conclusions from these results:
These recommendations were informed by our understanding of the dynamics of carbon lock-in. Developed reserves represent the oil, gas, and coal that the fossil fuel industry has already invested in extracting--the capital is sunk, the wells have been (or are being) drilled, the pits dug, and the related infrastructure constructed. Once a project is operating, there are economic, political, and legal factors that push for continued operation and present barriers to early closure.
Given the hard limit to how much fossil fuel can be extracted, and given the inertia behind existing projects, continuing to expand the footprint of the fossil fuel industry now risks two potentially overlapping outcomes: 1) Climate chaos, as the industry locks in levels of emissions that far exceed the Paris limits; and/or; 2) Economic chaos, from a sudden scramble to end fossil fuel production and use at a later date.
How has the new IPCC report adjusted our thinking?
The most important way the new IPCC has changed our thinking is that it has persuaded us that we need to aim to limit warming to 1.5 degrees, not just "well below 2 degrees." It's important to remember that 1.5degC exists as a goal within the Paris accord because some of the world's most climate-vulnerable nations demanded it, asserting this level of ambition as essential to their survival. The IPCC report provides powerful scientific backing for their call.
The report finds that exceeding 1.5degC of warming and hitting the 2degC threshold would put millions more people at risk of death, poverty, water and food shortages, and displacement from rising sea levels, while increasing the odds of irreversible, runaway ruptures in our climate system. We can significantly lessen the loss of human lives, whole communities, and ecosystems if governments interpret the upper limit of the Paris agreement--of keeping warming "well below" 2degC--to mean limiting it to 1.5degC.
Accordingly, we at OCI are shifting how we emphasize these goals in our own analysis, referring to 1.5degC first and as the primary aim when we discuss the Paris goals. We expect the IPCC report will encourage some governments and others to do the same.
One element of the new IPCC report has sparked questions and some confusion: the shifting size of the carbon budgets. As a basic concept, carbon budgets are relatively simple. They indicate how much CO2 can be emitted before the world reaches a certain temperature threshold. But calculating them depends on a variety of factors: how you measure the level of warming to date, how you measure temperatures (i.e., by air, sea, or a combination), how you define a "pre-industrial" baseline for human-caused emissions, exactly how many emissions have occurred since then, and how other greenhouse gas emissions influence the climate.
Since the IPCC's 5th Assessment Report, released in 2014, scientists have continued to examine the assumptions and methods that go into calculating carbon budgets. A much-debated paper released last year by Millar et al. (see our commentary on it here) proposed a new methodology, shifting the reference period from which models calculate carbon budgets to the recent past rather than pre-industrial times. Since the new reference period experienced slightly less warming than indicated by the models, the new methodology concluded that remaining carbon budgets for the 1.5degC and 2degC temperature thresholds may be larger as a result. The IPCC's 1.5-degree report adopted this new methodology, estimating that carbon budgets are roughly 300 gigatonnes (Gt) larger compared to those published in the 5th Assessment Report,[2] while noting that significant uncertainty remains around the size of this adjustment.
This is an active, ongoing scientific debate (for instructive overviews, read briefs from Climate Analytics and Carbon Brief). As such, it's not yet clear if the larger carbon budgets in the latest IPCC report fully reflect a new scientific consensus. In fact, it's so unsettled that the IPCC report gives two sets of budgets for each ambition level, based on different observational datasets. Some scientists have already said the report is too conservative, overstating remaining carbon budgets (in both versions) and understating risks. It's perhaps a case of unfortunate timing for the IPCC report, as it had to be written while that debate was just getting started.
Rather than waiting for a new consensus to be settled, let's take a look at what these larger budgets would mean if they're right. If we have a bit more space in global carbon budgets than previously thought, that's clearly a good thing. It would increase our chances of limiting catastrophic climate changes. Does this also imply there is some room to expand fossil fuel production?
The figure below shows how our original Sky's Limit calculation of developed fossil fuel reserves compares to the larger carbon budget sizes in the latest IPCC report (using the same 50 and 66 percent probability levels for 1.5degC and 2degC respectively). The bottom, darkest portions of the carbon budget bars show the budgets from the 5th Assessment Report (AR5), updated to reflect CO2 emissions through the end of 2017. The middle-shaded portions reflect the larger carbon budgets from the Special Report on 1.5 degrees (SR1.5) that use the same measure of warming as the 5th Assessment Report--global surface air temperature (GSAT). The top-shaded regions show the larger budgets based on a different temperature measure--global mean surface temperature (GMST), the average of air and sea surface temperatures.
For context, observational datasets generally use GMST, which is why the Millar et al. paper, based on observed warming to date, used them. On the other hand, the AR5, the scientific basis on which the Paris Agreement was reached, relied on GSAT. (For the sake of brevity, this is a simplification of the underlying science.) For assessing the Paris goals, one could argue against shifting goalposts. We look at both sets, since they both appear in the SR1.5.
Developed Fossil Fuel Reserves, Compared to Updated IPCC Carbon Budgets (GSAT and GMST) [3]
In each of these cases, developed reserves still significantly exceed the carbon budgets for a one-in-two chance of limiting warming to 1.5degC. Developed reserves are double the carbon budget for 1.5degC that's based on GSAT, after adding in optimistic estimates of future land use and cement manufacture emissions (which are more difficult to reduce than energy sector emissions).
With the larger budgets, there is some space between estimated emissions and the carbon budget limits for a two-in-three chance of staying with 2degC of warming (albeit just a sliver when looking at the Paris baseline of surface air temperature). If one sets aside the warnings of the IPCC report and accepts the upper limit of the Paris goals as written--keeping warming "well below" 2degC--one cannot reasonably interpret that bit of white space as a greenlight for new fossil fuel development. Rather, it offers a chance to manage the decline of fossil fuel extraction so that warming actually stays "well below"--rather than barely below--the 2-degree danger line.
Furthermore, given what the new report tells us about uncertainties in the budgets, a precautionary approach would imply aiming as low as possible. For example, the IPCC report authors caution, "Remaining budgets applicable to 2100, would approximately be 100 Gt CO2 lower...to account for permafrost thawing and potential methane release from wetlands in the future."
In short, while the larger budgets may give a welcome increase to our chance of success, there is still no room for new fossil fuel development.
The IPCC report makes clear that, irrespective of whether there is slightly more or less space in carbon budgets, there is no time to lose in rapidly reducing emissions. The report indicates that keeping warming within 1.5degC will require reducing carbon pollution by about 45 percent from 2010 levels by 2030 and reaching net zero emissions around 2050, as illustrated in the figure below from the report's Summary for Policymakers. Steering the world onto such a pathway will require"rapid and far-reaching" transitions and "deep emissions reductions in all sectors."
Global Total Net CO2 Emissions in Model Pathways Limiting Global Warming to 1.5degC
The report goes on to explain that the longer the world's countries delay in serious emissions cuts, the more they will be required to rely on so-called carbon dioxide removal (CDR) technologies in subsequent decades. The report also provides a warning of the ecological and social risks--and potential infeasibility--of this approach. "CDR deployed at scale is unproven and reliance on such technology is a major risk in the ability to limit warming to 1.5degC," the report states. This topic deserves its own dedicated blog post. For now, I'll leave it at this: Large-scale reliance on carbon dioxide removal technologies is, unsurprisingly, exactly what many fossil fuel companies point to in their own "climate" scenarios--because it would extend the lifetime of their fossil fuel business model.
Near-zero emissions by 2050 would mean close to zero fossil fuel extraction by 2050. If governments find the political will to heed the science and commit to a managed transition off of fossil fuel extraction, there will be a way. We have the clean technologies we need.
On the other hand, continuing to build out the fossil fuel economy risks putting the 1.5degC climate limit out of reach in the very-near future, and that would put millions of additional lives at risk. Rather than inviting climate and/or economic chaos, it's time for political leaders to plan seriously for climate success--to end the fossil fuel era in an equitable way.
Notes:
[1] Carbon budgets are taken from Table 2.2 of the AR5 Synthesis Report, and adjusted to remaining space from the start of 2018 (subtracting approximately 40 Gt CO2 per year for 2012-2017)
[2] See p. 16, footnote 14 of the SR1.5 Summary for Policymakers.
[3] The SR1.5 Summary for Policymakers cites the GSAT-based budget for a 50 percent chance at 1.5degC to be 580 Gt CO2 (see C1.3 on p. 16). The budgets using GSAT are in the process of being added to Chapter 2 of the SR1.5, and Table 2.2 in particular, to be consistent with the final Summary for Policymakers. The pending edits cite 1170 Gt CO2 as the GSAT-based budget for a 66 percent chance of limiting warming to 2degC. The GMST-based budgets for varying temperature limits and probabilities are found in the SR1.5 in Chapter 2, Table 2.2.
Since the Intergovernmental Panel on Climate Change (IPCC) released its new, must-read report on the urgency of limiting global warming to 1.5 degrees Celsius, we at Oil Change International have been receiving some common questions: What are the implications for our analysis of what the Paris accord's goals mean for fossil fuel production? What about the IPCC's use of larger carbon budgets, compared to its last major report? What, if any, new conclusions do we draw?
The quick summary is this: It's clear that the IPCC's 1.5-degree report clarifies and adds urgency to our call for a managed decline of fossil fuel production. Winding down the largest source of carbon emissions--the oil, gas, and coal extracted by the fossil fuel industry--will be essential to achieving deep cuts in carbon emissions within the next decade, as the report warns is necessary. In this post, I'll unpack three key takeaways:
(Questions such as, Is there hope? (yes), and, Is this possible? (yes), are also critical parts of the discussion right now. I focus here the technical aspects related to our analysis.)
First, a bit of background: We at Oil Change International (OCI) first analyzed the limits that the Paris goals imply for fossil fuel production in 2016, and the results were sobering. In our report, The Sky's Limit: Why the Paris Goals Require a Managed Decline of Fossil Fuel Production, we found that the oil, gas, and coal in existing fields and mines globally contain enough potential carbon emissions to push the world beyond the Paris climate goals.
We arrived at this result by using carbon budgets from the IPCC's 5th Assessment Synthesis Report, which reflected the scientific consensus at the time. We took budgets that were consistent with the range of the Paris goals--aiming to limit warming to 1.5 degrees Celsius (degC) or "well below" 2degC. We then compared those budgets to the potential cumulative carbon dioxide (CO2) emissions from already-developed fossil fuel reserves globally. You can see the results in the figure below.
Developed Fossil Fuel Reserves, Compared to Carbon Budgets in the IPCC 5th Assessment Report [1]
We drew two primary conclusions from these results:
These recommendations were informed by our understanding of the dynamics of carbon lock-in. Developed reserves represent the oil, gas, and coal that the fossil fuel industry has already invested in extracting--the capital is sunk, the wells have been (or are being) drilled, the pits dug, and the related infrastructure constructed. Once a project is operating, there are economic, political, and legal factors that push for continued operation and present barriers to early closure.
Given the hard limit to how much fossil fuel can be extracted, and given the inertia behind existing projects, continuing to expand the footprint of the fossil fuel industry now risks two potentially overlapping outcomes: 1) Climate chaos, as the industry locks in levels of emissions that far exceed the Paris limits; and/or; 2) Economic chaos, from a sudden scramble to end fossil fuel production and use at a later date.
How has the new IPCC report adjusted our thinking?
The most important way the new IPCC has changed our thinking is that it has persuaded us that we need to aim to limit warming to 1.5 degrees, not just "well below 2 degrees." It's important to remember that 1.5degC exists as a goal within the Paris accord because some of the world's most climate-vulnerable nations demanded it, asserting this level of ambition as essential to their survival. The IPCC report provides powerful scientific backing for their call.
The report finds that exceeding 1.5degC of warming and hitting the 2degC threshold would put millions more people at risk of death, poverty, water and food shortages, and displacement from rising sea levels, while increasing the odds of irreversible, runaway ruptures in our climate system. We can significantly lessen the loss of human lives, whole communities, and ecosystems if governments interpret the upper limit of the Paris agreement--of keeping warming "well below" 2degC--to mean limiting it to 1.5degC.
Accordingly, we at OCI are shifting how we emphasize these goals in our own analysis, referring to 1.5degC first and as the primary aim when we discuss the Paris goals. We expect the IPCC report will encourage some governments and others to do the same.
One element of the new IPCC report has sparked questions and some confusion: the shifting size of the carbon budgets. As a basic concept, carbon budgets are relatively simple. They indicate how much CO2 can be emitted before the world reaches a certain temperature threshold. But calculating them depends on a variety of factors: how you measure the level of warming to date, how you measure temperatures (i.e., by air, sea, or a combination), how you define a "pre-industrial" baseline for human-caused emissions, exactly how many emissions have occurred since then, and how other greenhouse gas emissions influence the climate.
Since the IPCC's 5th Assessment Report, released in 2014, scientists have continued to examine the assumptions and methods that go into calculating carbon budgets. A much-debated paper released last year by Millar et al. (see our commentary on it here) proposed a new methodology, shifting the reference period from which models calculate carbon budgets to the recent past rather than pre-industrial times. Since the new reference period experienced slightly less warming than indicated by the models, the new methodology concluded that remaining carbon budgets for the 1.5degC and 2degC temperature thresholds may be larger as a result. The IPCC's 1.5-degree report adopted this new methodology, estimating that carbon budgets are roughly 300 gigatonnes (Gt) larger compared to those published in the 5th Assessment Report,[2] while noting that significant uncertainty remains around the size of this adjustment.
This is an active, ongoing scientific debate (for instructive overviews, read briefs from Climate Analytics and Carbon Brief). As such, it's not yet clear if the larger carbon budgets in the latest IPCC report fully reflect a new scientific consensus. In fact, it's so unsettled that the IPCC report gives two sets of budgets for each ambition level, based on different observational datasets. Some scientists have already said the report is too conservative, overstating remaining carbon budgets (in both versions) and understating risks. It's perhaps a case of unfortunate timing for the IPCC report, as it had to be written while that debate was just getting started.
Rather than waiting for a new consensus to be settled, let's take a look at what these larger budgets would mean if they're right. If we have a bit more space in global carbon budgets than previously thought, that's clearly a good thing. It would increase our chances of limiting catastrophic climate changes. Does this also imply there is some room to expand fossil fuel production?
The figure below shows how our original Sky's Limit calculation of developed fossil fuel reserves compares to the larger carbon budget sizes in the latest IPCC report (using the same 50 and 66 percent probability levels for 1.5degC and 2degC respectively). The bottom, darkest portions of the carbon budget bars show the budgets from the 5th Assessment Report (AR5), updated to reflect CO2 emissions through the end of 2017. The middle-shaded portions reflect the larger carbon budgets from the Special Report on 1.5 degrees (SR1.5) that use the same measure of warming as the 5th Assessment Report--global surface air temperature (GSAT). The top-shaded regions show the larger budgets based on a different temperature measure--global mean surface temperature (GMST), the average of air and sea surface temperatures.
For context, observational datasets generally use GMST, which is why the Millar et al. paper, based on observed warming to date, used them. On the other hand, the AR5, the scientific basis on which the Paris Agreement was reached, relied on GSAT. (For the sake of brevity, this is a simplification of the underlying science.) For assessing the Paris goals, one could argue against shifting goalposts. We look at both sets, since they both appear in the SR1.5.
Developed Fossil Fuel Reserves, Compared to Updated IPCC Carbon Budgets (GSAT and GMST) [3]
In each of these cases, developed reserves still significantly exceed the carbon budgets for a one-in-two chance of limiting warming to 1.5degC. Developed reserves are double the carbon budget for 1.5degC that's based on GSAT, after adding in optimistic estimates of future land use and cement manufacture emissions (which are more difficult to reduce than energy sector emissions).
With the larger budgets, there is some space between estimated emissions and the carbon budget limits for a two-in-three chance of staying with 2degC of warming (albeit just a sliver when looking at the Paris baseline of surface air temperature). If one sets aside the warnings of the IPCC report and accepts the upper limit of the Paris goals as written--keeping warming "well below" 2degC--one cannot reasonably interpret that bit of white space as a greenlight for new fossil fuel development. Rather, it offers a chance to manage the decline of fossil fuel extraction so that warming actually stays "well below"--rather than barely below--the 2-degree danger line.
Furthermore, given what the new report tells us about uncertainties in the budgets, a precautionary approach would imply aiming as low as possible. For example, the IPCC report authors caution, "Remaining budgets applicable to 2100, would approximately be 100 Gt CO2 lower...to account for permafrost thawing and potential methane release from wetlands in the future."
In short, while the larger budgets may give a welcome increase to our chance of success, there is still no room for new fossil fuel development.
The IPCC report makes clear that, irrespective of whether there is slightly more or less space in carbon budgets, there is no time to lose in rapidly reducing emissions. The report indicates that keeping warming within 1.5degC will require reducing carbon pollution by about 45 percent from 2010 levels by 2030 and reaching net zero emissions around 2050, as illustrated in the figure below from the report's Summary for Policymakers. Steering the world onto such a pathway will require"rapid and far-reaching" transitions and "deep emissions reductions in all sectors."
Global Total Net CO2 Emissions in Model Pathways Limiting Global Warming to 1.5degC
The report goes on to explain that the longer the world's countries delay in serious emissions cuts, the more they will be required to rely on so-called carbon dioxide removal (CDR) technologies in subsequent decades. The report also provides a warning of the ecological and social risks--and potential infeasibility--of this approach. "CDR deployed at scale is unproven and reliance on such technology is a major risk in the ability to limit warming to 1.5degC," the report states. This topic deserves its own dedicated blog post. For now, I'll leave it at this: Large-scale reliance on carbon dioxide removal technologies is, unsurprisingly, exactly what many fossil fuel companies point to in their own "climate" scenarios--because it would extend the lifetime of their fossil fuel business model.
Near-zero emissions by 2050 would mean close to zero fossil fuel extraction by 2050. If governments find the political will to heed the science and commit to a managed transition off of fossil fuel extraction, there will be a way. We have the clean technologies we need.
On the other hand, continuing to build out the fossil fuel economy risks putting the 1.5degC climate limit out of reach in the very-near future, and that would put millions of additional lives at risk. Rather than inviting climate and/or economic chaos, it's time for political leaders to plan seriously for climate success--to end the fossil fuel era in an equitable way.
Notes:
[1] Carbon budgets are taken from Table 2.2 of the AR5 Synthesis Report, and adjusted to remaining space from the start of 2018 (subtracting approximately 40 Gt CO2 per year for 2012-2017)
[2] See p. 16, footnote 14 of the SR1.5 Summary for Policymakers.
[3] The SR1.5 Summary for Policymakers cites the GSAT-based budget for a 50 percent chance at 1.5degC to be 580 Gt CO2 (see C1.3 on p. 16). The budgets using GSAT are in the process of being added to Chapter 2 of the SR1.5, and Table 2.2 in particular, to be consistent with the final Summary for Policymakers. The pending edits cite 1170 Gt CO2 as the GSAT-based budget for a 66 percent chance of limiting warming to 2degC. The GMST-based budgets for varying temperature limits and probabilities are found in the SR1.5 in Chapter 2, Table 2.2.
The new Centers for Medicare and Medicaid Services administrator joins "a team of snake oil salesmen and anti-science flunkies that have already shown disdain for the American people and their health," said one critic.
Echoing a party-line vote by the U.S. Senate Finance Committee last week, the chamber's Republicans on Thursday confirmed President Donald Trump's nominee to head the Centers for Medicare and Medicaid Services, former televison host Dr. Mehmet Oz.
Since Trump nominated Oz—who previously ran as a Republican for a U.S. Senate seat in Pennsylvania—a wide range of critics have argued that the celebrity cardiothoracic surgeon "is profoundly unqualified to lead any part of our healthcare system, let alone an agency as important as CMS," in the words of Robert Weissman, co-president of the consumer advocacy group Public Citizen.
After Thursday's 53-45 vote to confirm Oz, Weissman declared that "Republicans in the Senate continued to just be a rubber stamp for a dangerous agenda that threatens to turn back the clock on healthcare in America."
Weissman warned that "in addition to having significant conflicts of interest, Oz is now poised to help enact the Trump administration's dangerous agenda, which seeks to strip crucial healthcare services through Medicare, Medicaid, and the Affordable Care Act from hundreds of millions of Americans and to use that money to give tax breaks to billionaires."
"As he showed in his confirmation hearing, Oz will also seek to further privatize Medicare, increasing the risk that seniors will receive inferior care and further threatening the long-term health of the Medicare program. We already know that privatized Medicare costs taxpayers nearly $100 billion annually in excess costs," he continued, referring to Medicare Advantage plans.
CMS is part of the Department of Health and Human Services, now led by Secretary Robert F. Kennedy Jr.—who, like Oz, came under fire for his record of dubious claims during the confirmation process. Weissman said that "Dr. Oz is joining a team of snake oil salesmen and anti-science flunkies that have already shown disdain for the American people and their health. This is yet another dark day for healthcare in America under Trump."
In the middle of Trump's tariff disaster, the Senate is voting to confirm quack grifter Dr. Oz to lead the Centers for Medicaid & Medicare Services.
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— Jen Bendery (@jbendery.bsky.social) April 3, 2025 at 12:29 PM
Oz's confirmation came a day after Trump announced globally disruptive tariffs and Senate Republicans unveiled a budget plan that would give the wealthy trillions of dollars in tax cuts at the expense of federal food assistance and healthcare programs.
"While Dr. Oz would rather play coy, this is no hypothetical. Harmful cuts to Medicaid or Medicare are unavoidable in the Trump-Republican budget plan that prioritizes another giant tax break for the president's billionaire and corporate donors," Tony Carrk, executive director of the watchdog group Accountable.US, said ahead of the vote.
"None of Dr. Oz's 'miracle' cures that he's peddled over the years will help seniors when their fundamental health security is ripped away to make the rich richer," Carrk continued. "And while privatizing Medicare may enrich Dr. Oz's family and big insurance friends, it will cost taxpayers far more and leave millions of patients vulnerable to denials of care and higher out-of-pocket costs."
Lee Saunders, president of the American Federation of State, County, and Municipal Employees (AFSCME), was similarly critical, saying after the vote that "at a time when our population is growing older and the need for access to home care, nursing homes, affordable prescription drugs, and quality medical care has never been greater, Americans deserve better than a snake oil salesman leading the Centers for Medicare and Medicaid Services."
"Dr. Mehmet Oz has been shilling pseudoscience to line his own pockets. He can't be trusted to defend Medicare and Medicaid from billionaires who want to dismantle and privatize the foundation of affordable healthcare in this country," the union leader added. "AFSCME members—including nurses, home care and childcare providers, social workers and more—will be watching and fighting back against any effort to weaken Medicare and Medicaid. The 147 million seniors, children, Americans with disabilities, and low-income workers who rely on these programs for affordable access to healthcare deserve nothing less."
"While your kids are getting ready for school, kids in Gaza were once against just massacred in one," said one observer.
Israeli airstrikes targeted at least three more school shelters in the Gaza Strip on Thursday, killing dozens of Palestinians and wounding scores of others on a day when local officials said that more than 100 people were slain by occupation forces.
Gaza's Government Media Office said that at least 29 people—including 14 children and five women—were killed and over 100 others were wounded when at least four missiles struck the Dar al-Arqam school complex in the Tuffah neighborhood of eastern Gaza City, where hundreds of Palestinians were sheltering after being forcibly displaced from other parts of the embattled coastal enclave by Israel's 535-day assault.
Al Jazeera reported that "when terrified men, women, and children fled from one school building to another, the bombs followed them," and "when bystanders rushed to help, they too became victims."
A first responder from the Palestine Red Crescent Society—which is reeling from this week's discovery of a mass grave containing the bodies of eight of its members, some of whom had allegedly been bound and executed by Israel Defense Forces (IDF) troops—told Al Jazeera that "we were absolutely shocked by the scale of this massacre," whose victims were "mostly women and children."
Warning: Video contains graphic images of death.
Horrifying scenes following the Dar Al-Arqam School Massacre!#Gaza pic.twitter.com/xOvuq3Zztx
— Dr. Zain Al-Abbadi (@ZainAbbadi11) April 3, 2025
An official from Gaza's Civil Defense, five of whose members were also found in the mass grave on Sunday, said: "What's going on here is a wake-up call to the entire world. This war and these massacres against women and children must stop immediately. The children are being killed in cold blood here in Gaza. Our teams cannot perform their duties properly.
Gaza Health Ministry spokesperson Zaher al-Wahidi said that the death toll was likely to rise, as some survivors were critically injured.
Dozens of victims were reportedly trapped beneath rubble of Thursday's airstrikes, but they could not be rescued due to a lack of equipment.
The IDF claimed that "key Hamas terrorists" were targeted in a strike on what it called a "command center." Israeli officials routinely claim—often with little or no evidence—that Palestinian civilians it kills are members of Hamas or other militant resistance groups.
Israel also bombed the nearby al-Sabah school, killing four people, as well as the Fahd School in Gaza City, with three reported fatalities.
Some of the deadliest bombings in the war have been carried out against refugees sheltering in schools, many of them run by the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA)—at least 280 of whose staff members have been killed by Israeli forces during the war.
The United Nations Children's Fund has called Gaza "the world's most dangerous place to be a child." Last year, U.N. Secretary-General António Guterres for the first time added Israel to his so-called "List of Shame" of countries that kill and injure children during wars and other armed conflicts. More than 17,500 Palestinian children have been killed in Gaza since October 2023, according to the Gaza Health Ministry.
Thursday's school bombings sparked worldwide outrage and calls to hold Israel accountable.
"While your kids are getting ready for school, kids in Gaza were once against just massacred in one," Australian journalist, activist, and progressive politician Sophie McNeill wrote on social media. "We must sanction Israel now!"
There were other IDF massacres on Thursday, with local officials reporting that more than 100 people were killed in Israeli attacks since dawn. Al-Wahidi said more than 30 people were killed in strikes on homes in Gaza City's Shejaya neighborhood, citing records at al-Ahli Arab Baptist Hospital in Gaza.
Al Jazeera reported that al-Ahli's emergency room "is overwhelmed with casualties and, as is so often the case over the past 18 months, the victims are Gaza's youngest."
Thursday's intensified airstrikes came as Israeli forces pushed into the ruins of the southern city of Rafah. Local and international media reported that hundreds of thousands of Palestinian families fled from the area, which Israel said it will seize as part of a new "security zone."
Human rights defenders around the world condemned U.S.-backed killing and mass displacement, with U.S. Sen. Bernie Sanders (I-Vt.)—whose bid to block some sAmerican arms sales to Israel was rejected by the Senate on Thursday—saying: "There is a name and a term for forcibly expelling people from where they live. It is called ethnic cleansing. It is illegal. It is a war crime."
Israeli Prime Minister Benjamin Netanyahu and Yoav Gallant, his former defense minister, are fugitives from the International Criminal Court, which last year issued arrest warrants for the pair over alleged war crimes and crimes against humanity. Israel is also facing a genocide case at the International Court of Justice.
According to Gaza officials, Israeli forces have killed or wounded at least 175,000 Palestinians in Gaza, including upward of 14,000 people who are missing and presumed dead and buried beneath rubble. Almost everyone in Gaza has been forcibly displaced at least once, and the "complete siege" imposed by Israel has fueled widespread and sometimes deadly starvation and disease.
"Working-class candidate v. billionaire political race. I'm here for it," wrote one longtime progressive strategist.
Dan Osborn, an Independent U.S. Senate candidate who struck a chord with working-class voters in Nebraska and came within striking distance of unseating his Republican opponent last year, announced Thursday that he's considering another run, this time challenging GOP Sen. Pete GOP Ricketts, who is up for election in 2026.
"We could replace a billionaire with a mechanic," Osborn wrote in a thread on X on Thursday. "I'll run against Pete Ricketts—if the support is there." Osborn said that he's launching an exploratory committee and would run as Independent, as he did in 2024.
Ricketts has served as a senator since 2023, and prior to that was the governor of Nebraska from 2015-2023. By one estimate, Ricketts has a net worth of over $165 million—though the wealth of his father, brokerage founder Joe Ricketts, and family is estimated to be worth $4.1 billion, according to Forbes.
A mechanic and unionist who helped lead a strike against Kellogg's cereal company, Osborn lost to Sen. Deb Fischer (R-Neb.) by less than 7 points in November 2024 in what became an unexpectedly close race.
Although he didn't win, he overperformed the national Democratic ticket by a higher percentage than other candidates running against Republicans in competitive Senate races, according to The Nation.
"Billionaires have bought up the country and are carving it up day by day," said Osborn Thursday. "The economy they've built is good for them, bad for us. Good for huge multinationals and multibillionaires. Bad for workers. Bad for small businesses, bad for family farmers. Bad for anyone who wants Social Security to survive. Bad for your PAYCHECK."
Osborn cast the potential race as between "someone who's spent his life working for a living and will never take an order from a corporation or a party boss" and "someone who's never worked a day in his life and is entirely beholden to corporations and party."
"We could take on this illness, the billionaire class, directly," he said.
Osborn, who campaigned on issues like Right to Repair and lowering taxes on overtime payments, earned praise from Sen. Bernie Sanders (I-Vt.), who told The Nation in late November that Osborn's bid should be viewed as a "model for the future."
Osborn "took on both political parties. He took on the corporate world. He ran as a strong trade unionist. Without party support, getting heavily outspent, he got through to working-class people all over Nebraska. It was an extraordinary campaign," Sanders said.
In reaction to the news that Osborn is exploring a second run, a former Sanders campaign manager and longtime progressive Democratic strategist Faiz Shakir, wrote: "working-class candidate v. billionaire political race. I'm here for it."