Climate change has already affected most of humanity. Here’s the proof

We always hear about climate change distressing different regions of the planet. But what’s the actual extent of the climate crisis? Now we have a more accurate figure. Researchers have calculated that 85% of the world’s population has already been affected by it, according to a review of tens of thousands of scientific reports. 

Image credit: Flickr / Alisdare Hickson

A team of researchers from the Mercator Research Institute on Global Commons and Climate Change (MCC) climate think-tank and Climate Analytics used machine learning to go through a massive amount of research published between 1951 and 2018. They identified about 100,000 papers with evidence on temperature changes, using it to create a global picture of how climate change is developing across the globe.

“Our study leaves no doubt that the climate crisis is already being felt almost everywhere in the world. It is also extensively scientifically documented,” Max Callaghan, lead author, said in a statement. “Our world map of climate impacts provides guidance for the global fight against global heating and for regional and local risk assessments.”

Callaghan and the team of researchers taught a computer algorithm to identify studies on climate change, generating a list of relevant papers. But the studies rarely made a direct link to global warming, so they decided to step up their game. They took the globe and divided it into a grid, identifying the places where the climate impacts matched trends on temperature and precipitation. 

On each grid, the researchers asked whether if it’s getting hotter, colder, wetter, or dryer outside the limits of natural variability, and then checked if this type of change matched forecasts from climate models. They found evidence of human-induced climate change impacts 80% of the world’s land area, where 85% of the population currently lives. 

An attribution gap

While observing an overall increase in climate studies, the researchers also identified an “attribution gap” – a lack of papers and data from low-income countries, making it very hard to understand climate impacts there despite observed changes. Evidence of impacts attributable to climate change is twice as common in high-income countries than in low-income ones.

“Developing countries are at the forefront of climate impacts, but we can see in our study there are real blind spots when it comes to climate impact data. Most of the areas where we are not able to connect the dots attribution-wise are in Africa”, Shruti Nath, contributing author, said in a statement. “This has real implications for adaptation planning.”

The findings come as countries are being pushed by civil society to present more ambitious climate goals at the United Nations climate change conference in Glasgow, Scotland, next month. A study earlier this year showed that with the current pledges the planet is on track for 2.7ºC global warming (4.9 degrees Fahrenheit) by the end of the century, triggering severe climate effects. 

The study was published in the journal Nature Climate Change.

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