“What are the fastest warming places on Earth and why are they warming so fast?”

— John, Grass Valley, Calif.

John, did my editor pay you to ask this?

Just this month, several of my colleagues on The Washington Post’s climate team were awarded a Pulitzer Prize for their reporting on this exact question.

Their analysis of global climate data showed the planet is heating up unevenly. Globally, average temperatures are a little more than 1 degree Celsius (1.8 degrees Fahrenheit) warmer than in the preindustrial era. But roughly one-tenth of the world’s surface area has already experienced 2 degrees Celsius of warming — an amount that U.N. scientists say will trigger dangerous climate impacts. In the United States, more than 70 counties have passed that threshold.

Over the past year, Washington Post journalists traveled to some of the fastest-changing places on the planet to understand why they’ve gotten so hot — and what that means for people who live there.

In New Jersey, lakes that once froze solid in winter are no longer safe for skaters. Waterfront homeowners in coastal Rhode Island are losing hundreds of feet of beach to rising sea levels. In Minnesota, a small army of scientists is working to plant new trees in forests that are threatened by the heat.

In other parts of the world, warming has been catastrophic. It’s killing off sea creatures in vital fishing grounds, such as the coasts of Uruguay and Angola. It’s melting Arctic permafrost, forcing communities in Alaska and Siberia to flee from the lands they had occupied for centuries.

In Qatar, temperatures are rising to deadly highs; to survive, the country has adopted the carbon-intensive practice of air conditioning the outdoors.

These rapid changes happen when global warming disrupts the geophysical processes that determine regional climate.

For example, temperatures in the Arctic summer — when the sun shines 24/7 — are typically moderated by sea ice, which reflects most of the sun’s rays back into space. But summertime ice cover at the pole has been rapidly shrinking. It’s now half a million square miles smaller than the average since 1981. More exposed ocean means more sunlight gets absorbed as heat, which melts the ice even further. This feedback loop is responsible for making the Arctic the fastest-warming place on the planet.

Changes in one part of the planet can destabilize climate systems elsewhere. Scientists say the loss of sea ice in the waters north of Japan has triggered a chain reaction that threatens an entire Pacific ecosystem. Historically, when the ocean surface froze it would expel huge amounts of salt into the waters below, creating a dense, nutrient-rich current that flowed East across the Pacific. With less of the ocean freezing, that current is weakening, and animals such as salmon are suffering as a result.

Climate change is also transforming the systems that circulate air around the globe. As the sun strikes the equator, huge columns of hot air rise up, then out toward the middle latitudes, then sink as they cool. In a warmer world, that air travels farther toward the poles, creating new “hot spots,” such as the one off the coast of Uruguay. Research suggests this warm ocean blob is shifting southward at a rate of 40 miles per decade.

Daniel Pauly, an influential marine scientist at the University of British Columbia, called places where temperatures have already gone up 2 degrees Celsius “chunks of the future in the present.” They illustrate how rising temperatures can make an ecosystem go haywire and render certain landscapes unlivable.

If the rest of the world is to avoid the same fate, United Nations scientists say, global greenhouse gas emissions must fall by 7.6 percent per year between now and 2030. But nations’ commitments under the Paris Climate Agreement were nowhere near ambitious enough to meet this target.

Even this year, when the covid-19 pandemic has shuttered factories, halted travel and caused unprecedented disruption to the global economy — at tremendous cost to the world’s most vulnerable people — emissions aren’t expected to decline more than 7 or 8 percent. Unless countries commit to serious changes, emissions next year are expected to shoot back up.

Humanity still has a lot of work to do.

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