By the end of the century, without any action to stop climate change, the average temperature in New York City could be like Atlanta today–an increase of 5.4 degrees Celsius or nearly 10 degrees Fahrenheit, more than the average in the middle of the 20th century. San Francisco, by contrast, might warm 3.9 degrees Celsius (7 degrees Fahrenheit). Utquiagvik, Alaska might warm 10.9 degrees Celsius–nearly a whopping 20 degrees Fahrenheit hotter.
A new map from the nonprofit Carbon Brief shows how the world is warming differently by location. The map splits the world into grid cells for each degree latitude and longitude–64,000 cells in total–and then gives the details about how much each area has already warmed because of climate change, and how much hotter it might get by the end of the century. Seeing how different parts of the world warm helps put the global threshold of 2 degrees Celsius of temperature rise into more context.
“There hasn’t been a good way for people to easily figure out how much has it warmed where I live, no matter where I live in the world,” says Zeke Hausfather, U.S. analyst for Carbon Brief. “We always talk about these sort of abstract global numbers like 2 degrees C, whereas in reality, the warming that has happened in the past and is projected to happen in the future differs a lot based on where people live.”
New York has already warmed 1.7 degrees Celsius (3 degrees F), versus 0.8 Celsius (1.44 degrees F) in San Francisco. The poles are warming faster than countries near the equator. “I didn’t realize just how fast the Arctic has been warming in recent years,” says Hausfather. Some parts of Alaska have already warmed 2 or 3 degrees Celsius. One patch of the Atlantic Ocean, cooled by melting ice in Greenland, is the only part of the world that isn’t currently warming.
Each degree or less of difference in every location has an impact. If the global average temperature rise is limited to 1.5 degrees instead of 2 degrees, for example, that could mean some coral reefs have a chance to survive and countries in the Mediterranean could cut their losses of freshwater in half. (The Paris climate agreement sets a target to limit warming to 2 degrees, but aims to go farther and limit it to 1.5).
Some changes will have global impacts–as the Arctic warms, it could mean harsher winters in Boston, sweltering summers in Paris, and stronger wildfires in California. As ice melts in Antarctica, sea level rise affects coastal cities everywhere. But local differences in temperature rise can also have more local impacts, from the number of uncomfortably hot days in a particular city to a reduction in how much food farms can grow in another region.
The future temperatures shown on the map come from four different scenarios. In the worst case, we do nothing. The worst scenario, called RCP 8.5, “is a world where we double down on coal,” Hausfather says. “We don’t care about climate at all. Renewables never really get that cheap. And we end up with over a thousand parts per million CO2 by 2100.” That’s the world in which New York City’s average annual temperature goes up almost 10 degrees Fahrenheit. With different choices–and a massive transformation of the global economy to cut emissions in line with the Paris agreement–the result would be very different. Cities would still get hotter even if the world quickly cuts emissions in the next decade; the average temperature in New York City might still rise another 0.3 to 1.7 degrees Celsius, or 3 degrees Fahrenheit. But the change might be something that’s more manageable than catastrophic.