Instead, they discovered something else: There is a disturbing inequality in the world of climate science.
Climate change studies are twice as likely to focus on the wealthiest countries in Europe and North America than on low-income countries like those in Africa and the Pacific Islands. This blind spot is a problem, because the countries of the South are and will continue to be more deeply affected by the climate crisis than the richer countries.
The ability to link the climate crisis to real impacts has increased dramatically over the past decade, as more people face the consequences of global warming, including deadly floods, destructive forest fires and a paralyzing heat. But it has been a challenge to collect and review the large amount of research, to fully understand the global impact.
In research published Monday in the journal Nature Climate Change, scientists used machine learning – computer training algorithms to detect patterns and predict outcomes – to analyze more than 100,000 climate change studies.
Compiling the results of all these studies would suggest that a large majority of the world – 80% of the land area, where 85% of the world’s population lives – is currently feeling the effects of the climate crisis. That’s a large percentage, but experts know the real number is even higher.
The authors called the research blind spot an “attribution gap.” Callaghan said the spread suggests that 85% is likely an underestimate.
Friederike Otto, co-head of the World Weather Attribution initiative, which was not involved in machine learning research, also said the study estimate was likely too low. Over the years, climatologists like Otto have said that the climate crisis will leave no room in the world untouched.
“The study focused on changes in average temperature and precipitation, rather than extremes, but we know that extreme heats change faster than average temperatures and extreme heats are increasing almost everywhere,” said Otto to CNN. “It’s likely that almost everyone in the world is now experiencing changes in extreme weather conditions as a result of human greenhouse gas emissions. “
“What we’re seeing here is that the evidence is unevenly distributed across countries,” Callaghan said. “And that’s really important because often when we’re trying to map or find out where the impacts of climate change are occurring, we often find few scientific papers in less developed or low-income countries. ”
Callaghan added that this attribution gap leaves people wondering if climate change is happening in these regions, even though climatologists firmly believe it.
“We want to try to emphasize that the absence of evidence is not evidence of absence,” he said.
The authors note in the study that an automated approach “does not replace careful expert assessment,” however, it can identify a large number of studies for a region that may point to the consequences of the original climate change. human.
Tom Knutson, senior scientist at the National Oceanic and Atmospheric Administration and co-author of the study, told CNN that the machine learning methodology has “a number” of limitations and weaknesses because it only takes into account certain climatic impacts – in this case man – precipitation and induced temperature changes.
If that took into account other impacts such as sea level rise, for example, he said the result could have suggested that “a larger fraction” of the world’s population has suffered from climate change.
A recent report from the World Meteorological Organization found that an extreme weather event or climate disaster has occurred every day, on average, somewhere in the world for the past 50 years, marking a five-fold increase over the past 50 years. of this period.
This summer alone has been filled with extreme weather events in the northern hemisphere: as the United States has been hit by a cocktail of drought-induced wildfires, devastating floods and a wave of Historic heat, China and Germany experienced deadly floods in July as southern Europe and Canada battled their own destructive wildfires.
Despite the extremes seen, the lack of substantial scientific evidence has the effect of limiting the changes that can be proposed or implemented in under-studied places, Callaghan said.
“It’s helpful to bring the literature and data together like this study did, which allows us to see where more data is needed and where there are gaps,” Otto said, pointing to previous studies. “Their finding of a gap in the Global South is similar to what we found last year, where we saw that extreme events are identified less often and are the subject of fewer attribution studies. when they occur in poorer countries. “
World leaders will meet at a critical UN climate meeting in less than a month, and one of the issues that will be discussed is how much funding developed countries can pledge to help countries in the world. South to move away from fossil fuels and manage the impacts of the climate crisis.
Callaghan said this new machine learning research delivers a key message to world leaders: Climate change is already happening and the planet will only continue to heat up, which means adaptation is essential as well as ‘stopping the use of fossil fuels. The new study provides insight into areas where more climate funds and climate research are needed, and it is up to world leaders to implement them.
“The world will continue to heat up until we stop burning fossil fuels, and there is simply no way around that,” he said. “And what we really need to recognize is that we need to change course and reduce emissions. “
Correction: This story has been updated to reflect the study published in the journal Nature Climate Change.