The world could theoretically still meet its goal of keeping global warming below 1.5 degrees Celsius, a level many scientists consider a dangerous threshold. Realistically, that probably won’t happen.
Part of the problem became apparent at COP27, the United Nations climate conference in Egypt.
While the countries’ climate negotiators successfully fought to “keep 1.5 alive” as the global goal in the official agreement, reached on November 20, 2022, some of their countries negotiated new fossil fuel deals, driven in part by the global energy crisis. Any expansion of fossil fuels — the main driver of climate change — makes it much more difficult to keep warming below 1.5 C (2.7 Fahrenheit) compared to 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 failed. And countries have done little in the past year to back up their commitments to reduce greenhouse gas emissions.
Positive steps have been taken, including advances in technology, falling renewable energy prices and countries committing to reducing their methane emissions.
But all signs now point to a scenario where the world is likely to exceed the 1.5°C limit by a large proportion. The World Meteorological Organization estimates that global temperatures have a 50-50 chance of reaching 1.5°C warming over the next five years, at least temporarily.
That does not mean that humanity can simply give up.
Why 1.5 degrees?
During the last quarter of the 20th century, climate change due to human activities became a matter of survival for the future of life on the planet. Since the 1980s, there has been mounting scientific evidence for global warming, and scientists have set global warming limits that cannot be exceeded to prevent the transition from a global climate crisis to a planetary-scale climate catastrophe.
There is consensus among climate scientists, including myself, that 1.5°C of global warming is a threshold above which humanity would be dangerously interfering with the climate system.
We know from the reconstruction of historical climate records that life has been able to thrive on Earth for the past 12,000 years at a global annual mean temperature of about 14 C (57 F). As you would expect from the behavior of a complex system, temperatures varied, but never got warmer than about 1.5 C during this relatively stable climate regime.
With the world warming by 1.2°C compared to pre-industrial times, people are already experiencing the effects of climate change in more locations, in more forms, and at higher frequencies and amplitudes.
Climate model projections clearly show that warming above 1.5C dramatically increases the risk of extreme weather events, more frequent, higher intensity wildfires, sea level rise, and changes in flood and drought patterns with implications for food system collapse, among other adverse impacts. will increase. And there may be abrupt transitions, the effects of which will lead to major challenges on a local to global scale.
Solid reductions and negative emissions
Significant reductions in carbon dioxide emissions are needed to meet the 1.5 target on this point, but that alone is not enough. It also requires “negative emissions” to reduce the concentration of carbon dioxide already put into the atmosphere by human activities.
Carbon dioxide lingers in the atmosphere for decades to centuries, so just stopping emissions won’t stop the warming effect. There is technology that can extract and trap carbon dioxide from the air. It still works on a very small scale, but corporate deals, such as Microsoft’s 10-year commitment to pay for carbon removed, could help scale it up.
A 2018 report from the Intergovernmental Panel on Climate Change found that meeting the 1.5°C target would require a 50% global reduction in carbon dioxide emissions by 2030 – plus significant negative emissions from both technology and natural sources by 2050 to about half of current daytime emissions.
Can we still hold the warming to 1.5 C?
Since signing the Paris climate agreement in 2015, countries have made some progress on their commitments to reduce emissions, but at a pace far too slow to keep warming below 1.5C. Carbon dioxide emissions are still increasing, as is the concentration of carbon dioxide in the atmosphere.
A recent report from the United Nations Environment Program highlights the shortcomings. The world is on track to produce 58 gigatons of carbon dioxide-equivalent greenhouse gas emissions by 2030 – more than double what it should be for the path to 1.5 C. The result should be an average global temperature increase of 2.7 C ( 4.9F). almost double the target of 1.5°C in this century.
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 yet near a plateau, 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 five to ten years.
How large the overrun will be and how long it will last depends critically on accelerating emission reductions and scaling up negative emissions solutions, including carbon capture technology.
At this point, nothing short of 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 climate change, primarily a transformation away from a fossil fuel-based energy system.
This article was republished on The Conversation, an independent, not-for-profit news site dedicated to sharing ideas from academic experts. It was written by: Peter Schlosser, Arizona State University. Do you like this article? subscribe to our weekly newsletter.
Peter Schlosser does not work for, consult with, own stock in, or receive funding from any company or organization that could benefit from this article, and has not disclosed any relevant affiliation outside of their academic tenure.