After COP27, all the signs are that the world has passed the 1.5 degree global warming limit – here’s what we can still do about it

The world could still, in theory, meet its goal of keeping global warming below 1.5 degrees Celsius, a level many scientists consider a dangerous threshold. Realistically, this is unlikely to happen.

Part of the problem was evident at COP27, the United Nations climate conference in Egypt.

While the nations’ climate negotiators were successfully battling to “keep 1.5 alive” as a global goal in the official deal, reached on November 20, 2022, some of their countries were negotiating new fossil fuel deals, spurred in part by global energy crisis. Any expansion of fossil fuels – the main driver of climate change – makes it much harder to keep warming below 1.5C (2.7 Fahrenheit) than in pre-industrial times.

Attempts at the climate talks to get all countries to agree to phase out coal, oil, natural gas and all fossil fuel subsidies have failed. And countries have done little to beef up their pledges to cut greenhouse gas emissions over the past year.

There have been positive moves, including advances in technology, falling renewable energy prices and pledges by countries to reduce their methane emissions.

But now all signs point towards a scenario where the world will breach the 1.5°C limit, probably by a considerable amount. The World Meteorological Organization estimates that global temperatures have a 50-50% chance of reaching 1.5°C of warming, at least temporarily, over the next five years.

This does not mean that humanity can simply give up.

Why 1.5 degrees?

During the last quarter of the 20th century, human-induced climate change became a matter of survival for the future of life on the planet. Since at least the 1980s, the scientific evidence for global warming has been increasingly robust, and scientists have set global warming limits that cannot be exceeded to avoid moving from a global climate crisis to a planetary-scale climate catastrophe.

There is a consensus among climate scientists, myself included, that 1.5°C of global warming is a threshold beyond which humanity would dangerously interfere with the climate system.

We know from reconstructed historical climate data that, over the past 12,000 years, life has been able to thrive on Earth at an annual global mean temperature of about 14°C (57°F). As one would expect from the behavior of a complex system, temperatures varied but never warmed by more than about 1.5°C during this relatively stable climate regime.

Today, with the world 1.2°C warmer than in pre-industrial times, people are already experiencing the effects of climate change in more places, more forms, and at higher frequencies and amplitudes.

Climate model projections clearly show that warming beyond 1.5°C will dramatically increase the risk of extreme weather events, more frequent wildfires with increased intensity, sea level rise, and changes in flood and drought patterns with implications for global health. collapse of food systems, among other negative impacts. And there can be sudden transitions, the impacts of which will translate into major challenges on a local and global scale.

Critical Points: Warmer ocean water is contributing to the collapse of the Thwaites Glacier, a major contributor to sea level rise with global consequences.

Strong reductions and negative emissions

Meeting the 1.5 target at this point will require large reductions in carbon dioxide emissions, but that alone is not enough. It will also require “negative emissions” to reduce the concentration of carbon dioxide that human activities have already put into the atmosphere.

Carbon dioxide stays in the atmosphere for decades to centuries, so just stopping emissions doesn’t stop its warming effect. There is a technology that can extract carbon dioxide from the air and lock it. It still only works on a very small scale, but corporate deals like Microsoft’s 10-year pledge to pay for removed carbon could help scale it.

A 2018 report by the Intergovernmental Panel on Climate Change determined that meeting the 1.5C goal would require reducing carbon dioxide emissions by 50% globally by 2030, as well as significant negative emissions from both technology and from natural sources by 2050 up to about half of current-day emissions.

A direct air capture project in Iceland stores captured carbon dioxide underground in basalt formations, where chemical reactions mineralize it.

Can we still keep the heating at 1.5C?

Since the Paris climate agreement was signed in 2015, countries have made some progress on their commitments to reduce emissions, but at too slow a pace to keep warming below 1.5°C. Carbon dioxide emissions are still on the rise, as are atmospheric carbon dioxide concentrations.

A recent report by the United Nations Environment Program highlights the shortcomings. The world is on track to produce 58 gigatons of carbon dioxide-equivalent greenhouse gas emissions in 2030, more than double what it should be on the path to 1.5C. The result would be an average global temperature increase of 2 7 C (4.9 F) this century, nearly double the 1.5 C target.

Given the gap between countries’ actual commitments and the emission reductions needed to keep temperatures at 1.5C, it seems virtually impossible to stay within the 1.5C target.

Global emissions are not close to plateauing, and with the amount of carbon dioxide already in the atmosphere, it is very likely that the world will reach the 1.5°C warming level within the next 5-10 years.

With current policies and commitments, the world will far exceed the 1.5°C target.
Climate action tracker

How large the overshoot will be and how long it will exist depends critically on accelerating emissions cuts and scaling up negative emissions solutions, including carbon capture technology.

At this point, an extraordinary and unprecedented effort to reduce emissions will save the 1.5C target. We know what can be done: the question is whether people are ready for a radical and immediate change in the actions that lead to change climate change, primarily a transformation away from a fossil fuel-based energy system.

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