After the United Nations annual climate conference earlier this month, scientists have a sobering message: the world is still not on the way to meeting its international climate goals.
A new article published in the magazine yesterday Nature climate change, is the latest study to drive home the point. Even if nations around the world keep their climate promises, the planet will likely still warm by more than 2 degrees Celsius.
The study focuses on the formal commitments to reduce carbon emissions made by the nations of the world under the Paris Agreement. These commitments, known as “Nationally Set Contributions” or NDCs, are the backbone of the agreement.
Prior to the conference in Glasgow, Scotland, the participating nations had the opportunity to update and strengthen their original Paris commitments. The success of Paris depends on the idea that leaders will improve their pledges fast enough to meet the goals of the agreement – keep global warming well below 2 degrees Celsius, and if possible below the more ambitious 1, 5 degrees Celsius.
But the updated pledges aren’t enough, according to the new study. All NDCs taken together are still warming between 2.2 and 2.9 ° C.
It is not the only study that has conveyed this message.
Every year the UN publishes a report that assesses the gap between recent climate promises and the goals of the Paris Agreement. Every year it comes to the conclusion that the world is falling short. This year’s report notes that the updated pledges would likely result in a warming of around 2.7 ° C.
Another similar analysis, released earlier this month by the climate research consortium Climate Action Tracker, suggested a likely warming of around 2.4 ° C.
The new study presents a wider range of possible warming. According to the authors, this is because it better takes into account all of the uncertainties associated with modeling future climate change.
The new study uses a number of seven different climate models to simulate the entire process of how the world might change in response to the Paris pledges by the end of the century.
The study takes into account the fact that not all countries have actually implemented policies that live up to their own climate promises.
It also simulates two possible paths to deliver on all pledges – one that assumes a policy to reduce emissions at certain rates, the other that assumes carbon prices will rise over time.
The study notes that there are minor differences in the amount of warming that result from each of these different assumptions. But she also notes that the differences between the individual models are even more significant.
The models themselves contain various built-in assumptions about how the world will respond to different climate policies, how energy needs and consumption evolve, and other factors that affect how quickly emissions could decrease over time.
Bottom line: It’s not easy to come up with an exact figure for future warming, even with specific commitments from nearly 200 countries. There are still many uncertainties, and they reflect bigger questions about how the world’s energy systems might change in the decades to come.
“The great uncertainties suggest that current policies and political commitments could still lead to a warming of 3 ° C in 2100,” said lead study author Ida Sognaes, a researcher at the Center for International Climate Research in Norway Explanation.
The suggestion that current commitments can be tied to an exact number – a number lower than the full range of likely possibilities – could “lead countries to believe that they are making good progress when the opposite may be the case” , added her.
Adding to the uncertainties is a new set of climate goals being introduced by countries around the world: pledges to achieve “net zero” carbon emissions, typically around the middle of the century. Net-zero promises have skyrocketed in the past two years, and dozen of countries have set goals for themselves.
However, most of these goals are not formally encapsulated in the NDCs. And most of them are not legally binding. That said, at the moment it’s mostly just goals.
The new study did not take these informal goals into account. But several other recent studies have looked at its possible effects. They found that the net zero goals could bring the world closer to the 2C goal, maybe even reach the goal – if everyone met them. That’s a big if (Climate wire, November 11th).
An analysis by the International Energy Agency released during the Glasgow negotiations found that the combination of updated pledges, net-zero targets and other global commitments concluded during the conference could limit global warming to 1.8 ° C.
On the other hand, a study was published earlier this month in science found that even if nations strengthened their existing NDCs and met their net-zero goals, the world would have a 60 percent chance of meeting the 2C goal (Climate wire, November 5th). So that means a good chance, but not a guarantee.
The findings are similar: accurate predictions about the future of the planet require precise knowledge of how the world will adapt and develop in the coming decades to its own climate policies. And scientists are still working on that.
On the other hand, the latest study makes a broad point about where the planet is headed. The world is slowly moving in the right direction – that’s the good news. It just has to go faster.
Reprinted from E&E News with permission from POLITICO, LLC. Copyright 2021. E&E News provides important news for energy and environmental professionals.