New framework makes it easier to track changes in the carbon budget
Researchers at the International Institute for Applied Systems Analysis (IIASA) have developed a new framework that will help scientists determine which circumstances affect the size of the remaining carbon budget and how these factors interact.
Over the last decade, research has shown that global warming strongly corresponds with rising atmospheric CO2 levels. This enables experts to calculate the remaining carbon budget, which is an estimate of how much CO2 can still be released while limiting temperature rise to a certain target level.
Policymakers, investors, and organizations are increasingly relying on carbon budgets to analyze the potential of low-carbon policies and technologies. Recent estimates have varied due to circumstances and natural processes that are more complicated to project than CO2 emissions. For example, there is uncertainty regarding the non-CO2 gases that also influence global warming, such as methane and aerosols.
In the current study, the researchers have created a new framework for understanding and tracking changes in the carbon budget. The team has concluded that the size of the remaining carbon budget can be determined by using five main factors: the amount of warming expected per ton of CO2 emissions, the amount of warming observed until today, the amount of future warming expected from gases other than CO2, whether warming stops instantly once CO2 emissions hit net zero, and whether there are any additional reinforcing cycles in the Earth system that have not been sufficiently considered.
Study lead author Joeri Rogelj is a senior researcher with the IIASA Energy Program.
“Our paper provides a new tool to clearly communicate up to date insights about carbon budgets. With the framework, changes can be pinpointed to single contributions that are much easier to understand. This should increase confidence in carbon budget estimates among policymakers, or at least their advisors, because changes in carbon budget estimates cease to appear to be random but rather are the result of clear progress of science in various areas,” explained Rogelj.
“The remaining carbon budget is a key quantity for defining the challenge of limiting climate change to safe levels. With this paper, we can understand and track this quantity much better. If you carefully look at carbon budgets, they become easy to understand. The fog is lifted, so to speak, and shows even more clearly that the remaining carbon budget to limit global warming to safe levels is tiny – action in the next decade is essential to stay within it.”
The study is published in the journal Nature.
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