It's been a tough year for the climate.
At the poles, ice melted like never before. In the tropics, hurricanes defied expectations. In temperate areas, extreme heat waves and cold snaps broke temperature records. Forests burned across the globe.
No one storm or heat wave can be directly attributed to climate change, but the warming world generally makes these weather events more common and more extreme.
Scientists say climate change likely played a role in the severe polar vortex event that engulfed North America, the deadly summer heat waves in Europe, and the devastatingly slow movement of Hurricane Dorian.
Taken together, the record-shattering extreme weather we saw throughout 2019 paints a worrisome picture of what's to come.
Atmospheric carbon dioxide has reached its highest level in at least 800,000 years.
Climate change is already leading to extreme weather that breaks records.
The year began with a record-shattering polar vortex that engulfed the US Midwest and eastern Canada, killing at least 21 people.
Scientists are starting to understand how rapid warming in the Arctic can make cold snaps like this more frequent.
Because Arctic temperatures are rising at double the rate of the rest of the planet, the difference between temperatures at the North Pole and lower latitudes is decreasing.
When spring arrived, the Midwest saw record flooding as the Mississippi and Missouri rivers swelled under heavy rainfall.
Extreme weather in the first six months of 2019 displaced a record 7 million people worldwide.
The Internal Displacement Monitoring Center said it expects 2019 to be
one of the worst years on record for this type of displacement.
The summer was sweltering. July was the hottest month ever recorded.
Two record-breaking heat waves swept across Europe — one in June, then another in July.
June 28, 2019 is now the hottest day ever recorded in France.
When the European heat wave washed over Greenland, it induced ice melt that even the most pessimistic climate models hadn't expected to see until 2070.
Similar heat waves swept the US and Japan in July.
Every month this summer saw record heat, continuing into October. So far, 2019 is the second-hottest year since records began 140 years ago.
The extreme heat depleted Arctic sea ice, which reached its lowest point ever for the month of July.
By September, the sea ice had shrunk to 1.6 million square miles — its second-lowest extent in the 41-year record.
Then coverage reached the lowest October extent ever recorded, at 32.2% below average.
At Earth's opposite pole, Antarctic sea ice reached its lowest June coverage on record.
Unprecedented wildfires raged across Siberia, Greenland, and Alaska all summer.
Those forest fires released more carbon dioxide than they ever had before.
Humans lit fires in the Amazon rainforest. Unusually hot, dry air made it easier for the flames to spread at unprecedented rates.
A different kind of extreme weather brewed in the Caribbean. Hurricane Dorian tied the record for the strongest Atlantic hurricane landfall ever.
Dorian made the most powerful landfall the Bahamas had ever seen. Then it sat over the island of Grand Bahama for nearly 24 hours.
Meanwhile, Hurricane Lorenzo traveled farther northeast in the Atlantic than any Category 5 storm had ever gone. It menaced parts of the UK.
Storm systems are complex, and scientists can't attribute any single storm to climate change. But global warming is making hurricanes stronger, wetter, and slower.
Meanwhile, satellites revealed that the world's largest, smelliest seaweed bloom now stretches from the coast of West Africa to the Gulf of Mexico.
Across the ocean, Venice flooded with its second-highest tide on record last week.