You Can Now Find Out How Climate Change Is Affecting Today’s Temperature

If temperatures are soaring at the World Cup in Qatar next month, spectators and athletes will be able to look online and see if climate change is to blame.

That’s thanks to the Climate Shift Index, an online tool that allows weather forecasters and residents to see how greenhouse gas emissions are affecting daily temperatures. A version of the index that tracks temperatures in the continental U.S. launched this summer. Today, Climate Central, the nonprofit climate science organization that developed the index, released a broader version that allows users to see how global warming is influencing local temperatures anywhere around the world.

The index works through a bit of clever statistics—every day, a computer system compares current temperatures around the world to historical data and the output of dozens of climate models in order to determine how likely those conditions would be in a world without humanity’s greenhouse gas emissions—and how much more likely a century of burning fossil fuels may have made them.

The index presents those findings on a color-coded map: Yellow means global warming made current temperatures 1.5 times more likely; dark red indicates that the current temperatures were five times likelier to occur due to climate change, an “exceptional” climate fingerprint.

The rollout of the worldwide Climate Shift Index is the latest project in the growing field of attribution science, where climate scientists attempt to show connections between weather events and rising greenhouse gas emissions. Some such analyses, such as figuring out the role climate change might have played in a major heat wave, used to be difficult, months-long affairs, but scientists have worked to speed up and standardize the methods in recent years.

Now, attributing regional or local temperature to climate change is relatively straightforward scientifically, which is why the Climate Shift Index is able to run through the calculations for all the world’s temperatures every day. Doing the same for other weather, like rainfall, is more difficult, and requires more time. Proving out the full extent of climate change’s impact on the most extreme weather events also requires more specialized analysis, such as in the case of the Pacific Northwest heat dome last summer, which scientists at World Weather Attribution concluded would have been “virtually impossible,” without the effects of human-caused climate change.

The work on the global Climate Shift Index has led to some interesting—and troubling—findings. The researchers who developed the tool examined weather data from the past year and found that climate change affected temperatures for 96% of the world’s population. But the effects were especially strong near the equator, and on small islands where warmer ocean waters are boosting temperatures on land. “It’s just really clear that in a lot of those places they’re dealing with climates that are just permanently altered from what they were before,” says Andrew Pershing, the director of climate science at Climate Central.

The hope now is that people will be able to use the Climate Shift Index to see climate change impacts that may have otherwise gone unnoticed—a balmy winter day in Stockholm, for instance, might have a dark red signature on the Climate Shift Index map. It can also help illustrate just how widespread those effects are, showing where climate change is bringing extreme heat, even beyond those few heat waves that make international news. “There were events in other places [last year] that didn’t get the same level of attention, even though they had arguably as much or more of an impact on people,” says Pershing. “We’re hoping the tool will help people see those events more clearly.”