The best possible future – one with fewer climate disasters, extinctions and human suffering – involves limiting global warming to 1.5 degrees Celsius. But for this to happen, a new report warns, greenhouse gas emissions must begin to decline by 2025.
“We are on a fast track to climate disaster,” UN Secretary-General António Guterres said Monday as he announced a new report by the UN’s top climate body, the Intergovernmental Panel on Climate Change.
“This is not fiction or exaggeration,” he added. “That’s what the science tells us will result from our current energy policies.” We are heading for global warming of more than double 1.5 degrees.”
In 2016, almost all countries signed the Paris Climate Agreement, pledging to avert the worst climate impacts by limiting global warming to well below 2 degrees Celsius, ideally to 1.5 degrees Celsius, compared to pre-industrial levels . But the world has already warmed by 1.1 degrees Celsius, and this new report makes abundantly clear that the temperature targets could soon be missed if people do not make immediate and radical changes to the way we live, from how we get energy and food to how we build and move.
“It is now or never if we want to limit global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit),” Jim Skea of Imperial College London, one of the report’s co-authors, said in a statement. “Without immediate and deep reductions in emissions across all sectors, that will be impossible.”
Skea was one of hundreds of scientists around the world who contributed to the report called “Climate Change 2022: Mitigation of Climate Change,” the third and final installment of the IPCC’s sixth climate assessment. The previous installments, published in recent months, focused on summarizing the climate impacts that are already here and what is likely to come, as well as documenting ways to adapt to these impacts.
Faced with worsening climate impacts, from intensifying heat waves and floods to growing food shortages, humans have spent the last decade adding fuel to the fire by continuing to spew more carbon dioxide and other greenhouse gases into the atmosphere than ever before.
Global emissions averaged about 59 gigatonnes of carbon dioxide equivalent in 2019, about 12% higher than in 2010 and 54% higher than in 1990, according to the new report. This is an incredible increase.
But the blame for increased emissions does not fall equally on everyone.
“The 10% of households with the highest per capita emissions contribute a disproportionately large share of global [greenhouse gas] emissions,” according to a summary of the new report. For example, in 2019, small island developing States are estimated to have emitted 0.6% of global greenhouse gas emissions.
The only way to prevent widespread climate damage is to halt this trend immediately. To keep the 1.5 degrees Celsius future alive, according to the report, people around the world must collectively peak their emissions by 2025 and then reduce emissions by 43% by 2030. This includes reducing the powerful greenhouse gas methane by 34% by 2030.
Finally, by 2050, people must achieve net zero emissions, which is when they are putting into the atmosphere the same amount of emissions as they are taking out of it.
Even if all these deadlines are met, scientists warn that it is still likely that global average temperatures will temporarily exceed or “exceed” 1.5 degrees Celsius before falling back below that level by the end of the century.
Keeping even a 2.0 degree Celsius future within reach involves peaking global emissions by 2025, according to the report, then reducing emissions by 27% by 2030 and reaching net zero emissions by the early 1970s.
Perhaps the single biggest way to reduce emissions quickly is to switch from fossil fuels to renewable and other alternative energy sources. Limiting warming to 1.5 degrees, climate models suggest, involves reducing global use of coal, oil and gas in 2050 by about 95%, 60% and 45% based on 2019 marks.
“Climate change is the result of more than a century of unsustainable energy and land use, lifestyles and consumption and production patterns,” Skea said. “This report shows how taking action now can move us towards a fairer and more sustainable world.”
The release of the report comes as Russia’s war in Ukraine has driven up energy costs, and as the conversation in Europe, the United States and elsewhere has shifted rapidly away from Russian fossil fuels.
“We are facing challenging times at the moment. We have learned about this brutal war in Ukraine,” Petteri Taalas, director-general of the World Meteorological Organization, told a news conference on Monday, before linking the ground fighting to the fight to limit climate change. “At best, this would accelerate the reduction of fossil energy use and also accelerate the green transition.” At worst, climate change mitigation interests will be challenged by this development.”