The carbon budget estimates how much more C02 we can emit into the atmosphere and still keep global warming below 1.5˚ C. Find out why a new study found that we only have a 50% chance of meeting our climate targets.
It will soon be eight years since the historic 21st Conference of the Parties (COP21) meeting in Paris. I can still remember the jubilation when representatives from nearly 200 countries finally reached an agreement on climate change.
Known as the Paris Agreement, its goal was to limit global warming to well below 2˚ C, and ideally, to work to keep warming below 1.5˚ C by 2030. The lower target came from concerns raised by vulnerable and small island nations, who believed the damage caused by a 2˚ increase was unacceptable for their populations.
Celebrations erupted around the world when the parties announced the agreement. Here in Canada, our environment minister, Catherine McKenna, said, “I’m really thrilled Canada was able to play an active part of it.”
“World’s Greatest Diplomatic Success”
Minister McKenna went on to say, “It is an incredible day today, to see 195 countries come together and reach consensus on a climate change agreement that is going to make huge changes in terms of how we tackle possibly devastating consequences on climate changes.“ Writing for The Guardian, Fiona Harvey called it, “the world’s greatest diplomatic success.”
Dr. Robin Lamboll began studying what humans emit into the atmosphere, the effects it will have on us, and what we can do about them, shortly before the Paris Meeting. Professor Lamboll is currently a Research Associate in Climate Science and Policy at Imperial College London.
Professor Lamboll is also the lead author of a study the journal Nature Climate Change published this week. It’s the most up-to-date and comprehensive analysis of the global carbon budget to date.
Progress Report on Meeting Climate Targets
The carbon budget estimates how much carbon dioxide we can emit into the atmosphere and still keep global warming below our temperature goals. It’s a way of reporting humanity’s progress toward meeting our climate targets.
Nobody’s going to be celebrating this study’s findings. The researchers estimate that if emissions continue at 2022 levels, humanity will have exhausted the carbon budget by 2029.
If that happens, we’ll be stuck with global warming above the 1.5˚ C goal. The world has less than 250 gigatonnes left in its carbon budget, and we’re emitting roughly 40 gigatonnes annually.
Carbon Budget Lower Than Previously Thought
Part of the issue is that our carbon budget is lower than other researchers had estimated. Our greenhouse gas emissions are increasing instead of decreasing, mainly because we keep burning fossil fuels.
“Our finding confirms what we already know – we’re not doing nearly enough to keep warming below 1.5° C,”Professor Lamboll explained. “Estimates point to less than a decade of emissions at current levels.”
We still have a window of opportunity, but time is running out. As Professor Lamboll puts it, “The lack of progress on emissions reduction means that we can be ever more certain that the window for keeping warming to safe levels is rapidly closing.”
Scientists’ Findings Align With Other Research
The scientists’ findings align with other research. As Professor Joeri Rogelj also of Imperial College London said, “This carbon budget update is both expected and fully consistent with the latest UN Climate Report.”
That 2021 report estimated that humanity had a one in three chance of finding itself with the small remaining carbon budget we now face. “This shows the importance of not simply looking at central estimates, but also considering the uncertainty surrounding them.” Professor Rogelj pointed out.
Our global climate is a complex system, and it’s not easy to make these kinds of calculations accurately. Scientists rely on models that don’t always take factors like other greenhouse gas emissions into account.
Insights Into Climate Response to Net- Zero Carbon Future
The scientists used a more up-to-date dataset and also used a more sophisticated climate model. Their improved methodology also provided some insights into the ways the global climate might respond to a future in which emissions produced and emissions removed from the atmosphere balance out.
That’s what scientists mean by a “net-zero” carbon future. It’s not clear to scientists how the elements of the global climate system will respond as we get closer to our net-zero goal.
Effects like ice melting, methane discharges and altered ocean currents might keep global warming going. On the other hand, planting and encouraging more vegetation might create carbon sinks that would absorb enough C02 to cool global temperatures.
Opposing Warming and Cooling Influences
“At this stage, our best guess is that the opposing warming and cooling will approximately cancel each other out after we reach net zero,” Professor Lamboll said. “However, it’s only when we cut emissions and get closer to net zero that we will be able to see what the longer-term heating and cooling adjustments will look like.”
Since we can’t predict how all these ambiguities will play out, the researchers are calling for urgent action. Of course, the Paris Agreement called for urgent action on global carbon emissions eight years ago, yet they’re still increasing instead of decreasing.
We’ve known that carbon dioxide in the atmosphere warms the climate since Swedish scientist Svante Arrhenius published a scientific paper on the subject in 1896. The expert consensus on the climate crisis has been clear since the 1970s.
And Another Thing…
These updated budget estimates are part of the new story that humanity needs about our planet’s natural environment and our place within it. The researchers’ findings remind us of the need to see ourselves as part of nature rather than its masters.
The carbon budget points out Earth’s limited capacity to absorb and regulate our emissions into the atmosphere from human activity. The scientists are calling for more responsible stewardship of our planet instead of merely extracting resources from it.
Professor Lamboll concluded by saying, “Every fraction of a degree of warming will make life harder for people and ecosystems. This study is yet another warning from the scientific community. Now it is up to governments to act.”
We always have more to learn if we dare to know.
Learn more:
Window to avoid 1.5°C of warming will close before 2030 if emissions not reduced
Assessing the size and uncertainty of remaining carbon budgets
Carbon Offsets Aren’t Working and Need Reforms
UN Report Calls for Urgent Climate Action
Carbon Taxes Are the Best Way to Fight Climate Change
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