Historical emissions caused the climate crisis. But what we do today is what will define its course, according to a study

They call for an end to fossil fuel subsidies due to global warming 0:46 (CNN) — The historical emissions of greenhouse gases by humans are the cause of the climate crisis in which the world finds itself today. But it is the amount emitted now and in the years to come that will determine whether humanity can avoid catastrophic climate change.
This is the main conclusion of a new study published this Monday in the academic journal Nature Climate Change, according to which, even if the world reduced its emissions to zero today, there would be a 42% chance of reaching 1.5 ° C of warming above pre-industrial levels within a decade. That probability increases to 66% if the world waits until 2029 to reach zero emissions. The Dixie Fire charred nearly half a million acres in California in 2021, becoming the second largest fire in state history. However, reaching zero emissions in this decade is shaping up to be a pipe dream at the moment, considering that global emissions continue to rise, and will continue for years to come. A UN report shows that new and updated commitments on emissions will only reduce 7.5% of current rates by 2030. In addition, China, the world’s largest emitter, will not reach zero emissions until 2060. The study also shows that if the world emitted nothing today, there would be only a 2% chance of exceeding the more severe 2°C warming threshold. But that probability also increases to 66% if the world waits another 35 years before reaching zero emissions. If zero emissions were achieved today, temperatures would peak within a decade, according to the study, and as the concentration of greenhouse gases in the atmosphere declines slowly, as long as it stays low, that peak will be followed by a long and slow cooling period. According to the study, “future warming is primarily driven by future rather than past emissions, so society is not geophysically committed to exceeding key levels of global warming before reaching them.” The findings send a sobering message: the world must accelerate its goal of reaching net zero, where as little greenhouse gas as possible is emitted and the rest is offset. But it also sends a hopeful message: that there is still a good chance of keeping the climate crisis under control if deep and sustained cuts in emissions are made. And the sooner the better. “What this study has taught me is that the window of opportunity to reduce our emissions to avoid temporarily exceeding 1.5°C is rapidly closing,” Kyle C. Armour, study co-author and associate professor, told CNN. of oceanography and atmospheric sciences at the University of Washington in Seattle. [reducir las emisiones] almost immediately.” Armor adds that he believes focusing on capping 1.5°C as a policy goal may become “unrealistic” and that the world is more likely to think about tackling 2°C. “That’s my personal opinion, simply because that window of opportunity is so short, and it really has to happen this decade,” he said. “Reducing emissions to zero is not practical on a global scale. The other side of the coin is that I’m very optimistic about keeping warming close to or below two degrees, because we have several decades to figure it out.” Earlier this year, the Intergovernmental Panel on Climate Change (IPCC) released its latest scientific evidence showing that if the world warms 1.5°C above pre-industrial levels, even temporarily, some impacts could take thousands of years to develop. be reversed or, in some cases, completely irreversible. This includes highly vulnerable ecosystems in the Arctic, mountains and coasts. The melting of ice sheets and glaciers, for example, will accelerate sea level rise. Forests, peatlands and permafrost, places where greenhouse gases are naturally absorbed and stored, will also be at risk of becoming emitters, causing a ca much higher slowdown. With 2°C warming, up to 18% of terrestrial species will be at risk of extinction. In the case of humans, up to 3 billion people worldwide will suffer from chronic water scarcity, according to the IPCC. The world is already at least 1.1°C warmer than pre-industrial levels. The scientists behind the study used climate models to estimate the change in Earth’s temperature if emissions were reduced to zero in 2021 and all subsequent years through 2080, under different scenarios. The researchers also took into account the role of different greenhouse gases and their concentrations in the atmosphere, as well as aerosols and ozone depletion. While the burning of fossil fuels is the main driver of climate change, aerosols—emissions of tiny air pollution particles—also have a cooling effect, though not enough to offset the negative impact of using coal, oil, and the gas. While much of the world’s attention has been focused on reducing carbon dioxide (CO2) emissions, which is critical to ending the climate crisis, Armor said solutions must also take “climate forcers” into account. short-lived, such as the greenhouse gas methane and aerosols. “Because we’re committing to a few tenths of a degree more warming as we lose aerosols, they actually mask that warming,” he said. “What this means is that we are geophysically committed to these temperature levels, like 1.5 and 2°C, maybe five or 10 years before we actually reach those levels, if we continue with our emissions; because as we continue with our emissions , we continue with our contamination by aerosols”. Kim Cobb, director of the Global Change Program at the Georgia Institute of Technology, said the study demonstrates the importance of understanding the evolution of different types of emissions. “Regarding our ability to predict the timing and magnitude of the warming spike, this work shows that you have to read the fine print,” Cobb, who is not involved in the study, told CNN. “This may sound pretty overwhelming, but when you’re talking about a few tenths of a degree Celsius, that’s a big deal in terms of global warming levels.” Cobb said the latest study not only builds on existing climate research, but also underscores what many in the scientific community already knew to be true. “We only have a handful of years to reduce emissions and have any hope of limiting global warming to 1.5°C,” Cobb said. “This opportunity is slipping away from us with each additional year of inaction.”