By Catastrophe? They warn that in less than 100 years the Earth will be 2 degrees warmer
The first study used statistical analysis to show that there is a 95% chance that the Earth will warm more than 2 degrees by the end of the century and just a 1% chance that the increase will be below 1.5 degrees.
“Our model is based on information that already shows the effect of existing policies to mitigate the emission (of greenhouse gases). Reaching the goal of a warming of less than 1.5 degrees will require the carbon intensity to decline much faster than in the recent past, "said Adrian Raftery, author of this paper.
The second study looked at past greenhouse gas emissions and the burning of fossil fuels to show that even if humans stopped burning fossil fuels right now, the Earth will continue to warm, with a temperature rising by about 2 degrees by 2100.
Furthermore, it concluded that if emissions continue for more than 15 years, a much more likely scenario than sudden interruption, the Earth's temperature could rise by as much as 3 degrees. "Even if we stop burning fossil fuels today, the Earth will continue to slowly warm up," said Thorsten Mauritsen, author of the second study.
Taken together, the similar results from the two investigations present a stark reality.
The studies were completed before the United States withdrew from the Paris Agreement on Climate Change, by decision of President Donald Trump.
"Clearly, the US exit from the Paris Agreement will make it much more difficult to reach our goals of increasing 1.5 or maximum 2 degrees," explained Raftery.
Why 2 degrees?
The 2-degree mark was established by the Paris Agreement signed in December 2015. But it had already been proposed as a limit by Yale economist William Nordhaus, in 1977.
According to the researchers, the climate has been warming since the burning of fossil fuels began in the 19th century, during the Industrial Revolution.
If we exceed that mark, scientists estimate that life on our planet as we know it today will change completely. Possible consequences include rising sea levels, mass extinctions, extreme droughts, increased forest fires, more intense hurricanes, reduced crops and fresh water, and melting ice in the Arctic.
The impact on human health will also be profound. Increasing temperatures and changes in the climate will worsen air quality and there will be more water and food contamination, as well as more infections transmitted by mosquitoes and ticks and greater stress on mental health, according to a recent report by the Society of the Medical Consortium on Climate and Health.
Currently, the World Health Organization (WHO) estimates that 12.6 million people die globally from pollution, extreme climates and climate-related diseases. It is expected, according to the international body, that between 2030 and 2050 climate change will cause an additional 250,000 deaths.
The impact of our past
The first study used population, carbon emissions, and gross domestic product information from 152 countries over the past 50 years.
The other interesting finding that Raftery and his colleagues found in that research was that population is not an influencing factor.
"This is due to the fact that much of the population of the future will grow up in Africa, in countries whose carbon emissions are currently very low," Raftery explained.
In the second study, Mauritsen and his co-author Robert Pincus combined observations of past global warming and how much heat and how much carbon is being absorbed by the ocean. His discovery is that although CO2 lasts a very long time in the atmosphere, the absorption capacity of the ocean will perhaps reduce the estimates of global warming by 0.2 degrees.
The problem is that "the study does not care about future emissions," said Mauritsen. "Our study can be a benchmark for calculating how far we are from reaching various temperature-related targets," he added.
What can we do?
The researchers say that the key to avoiding these worrying conclusions lies in a change in public policy.
"The next few years will be critical in the fight against climate change," said Dargan Frierson, co-author of the first study. "Will we work on installing clean energy or will we get stuck with the old sources of pollution? If we do not act quickly, it is better that we prepare for the severe consequences of living in a much hotter world, "he said.
"There are only two realistic ways to avoid a long-term disaster: increase financial incentives to reduce greenhouse gas emissions and considerably increase resources to do research that leads us to at least implement partial technological repairs", he considered for his part Dick Startz, economist and co-author of the second study.
"Nothing is free. But the two options are better than the catastrophe that is drawn at the end of the road ”, he concluded.