fb-pixelClimate change 2023: Record-breaking heat, flooding, and wildfires affecting millions in July Skip to main content

Punishing heat, flooding, wildfire: Does it seem like weather extremes are everywhere? You’re right.

A damaged car stands in front of a burned tree near Athens, Greece. Two wildfires threatened homes in areas outside Athens, where strong winds made the flames difficult to contain.Petros Giannakouris/Associated Press

The summer of 2023 is shaping up to be a season of climate extremes around the planet, with millions of people affected by heat waves, wildfires, and flooding.

Scientists believe human-caused climate change plus the El Nino weather pattern are contributing to the world’s weather woes. Here’s a look at some of what’s been going on in recent weeks:

The US southern heat wave

A person tries to cool off in the shade in Phoenix. Ross D. Franklin/Associated Press

The Southwest is expected to continue to sizzle under a “dangerous, long-lived and recordbreaking heat wave” well into next week, the National Weather Service says. The mid-South, Southeast, and Gulf Coast will also stifle under a combination of heat and humidity that will make it feel like 105 to 110 degrees through early this weekend before returning closer to the averages.


Phoenix is a furnace. The weather service says the desert city of more than 1.6 million people experienced a record high of 119 degrees Wednesday and Thursday. A record-tying 118-degree day was predicted Friday before easing by a couple of degrees.

Phoenix by Thursday had seen 21 straight days of highs over 110, a record for a major city.

The heat wave is expected to continue across the Southwest for at least another week, forecasters said. More than 116 million people were under weather service heat alerts on Friday.

CNN reported Wednesday that the first heat alerts went out June 10 and thousands of records had already fallen from Florida to California.

Key messages on Thursday about the US heat waveNWS

Tub-worthy ocean temperatures off Florida

A person looked out over an extremely warm Atlantic Ocean at sunrise last week in Miami Beach. High ocean temperatures are a concern because they threaten coral reefs and supercharge hurricanes and other tropical storms.Joe Raedle/Getty

The Caribbean Sea and southern Gulf of Mexico, including around southern Florida, have been experiencing a marine heat wave for several months. It is expected to persist through October 2023, according to the National Oceanic and Atmospheric Administration.

Sea surface temperatures at certain locations off Florida climbed to the high 90s in recent days.

One sensor in shallow, dark water reached a reading of 98 degrees, which is only two degrees cooler than some people keep their hot tubs.


The temperatures around southern Florida are the warmest since records began being kept in 1981, according to NOAA.

The heat waves “cause stress to corals and other marine ecosystems” and could strengthen hurricanes and other tropical storms that pass through the region, NOAA said.

NASA's Short-term Prediction Research and Transition (SPoRT) Sea Surface Temperature product shows warm temperatures throughout the Gulf of Mexico on Thursday.NASA

The world’s warmest June... followed by the warmest month ever?

The heat is not just cooking the United States. It’s global.

NOAA says June 2023 was Earth’s warmest June on record. The average global surface temperature (both land and ocean) was 1.89 degrees above average. That was also 0.23 of a degree warmer than the previous record set in June 2020.

Daily records for the globe have continued to fall this month. Some scientists estimate that the first two weeks of July were the hottest ever, the New York Times reported.

Based on the way things are going, It is “virtually certain” that July will end up being not only the warmest July ever, but the warmest month of any month ever recorded, a climate scientist told The Washington Post. The records go back to the mid-1800s.

NOAA experts have also estimated there is a greater than 99 percent chance that the year 2023 will rank among the 10 warmest years on record and a 97 percent chance it will rank among the top five.

The most sea ice ever melted

With temperatures on the rise, this may come as no surprise. The extent of sea ice in June 2023 was the lowest ever recorded for the month, NOAA said.


“This primarily was a result of the record-low sea ice in the Antarctic that occurred for the second consecutive month,” NOAA said.

The previous record low sea ice extent was in June 2019. Sea ice shrank another 330,000 square miles, compared with the 2019 number.

It's winter in Antarctica and sea ice is growing but below the normal rate. Scientists say that's a key reason sea ice globally hit record lows in June.National Snow and Ice Data Center

Record wildfires in Canada

A scorched car rests in the yard of a home destroyed by a wildfire in the East Prairie Metis Settlement, Alberta.Noah Berger/Associated Press

You’ve seen - and maybe even smelled - the evidence yourself.

The smoke from Canadian wildfires, propelled long distances by atmospheric currents, has caused hazy skies, fine particle pollution, and even the smell of smoke in the United States, including in Boston.

The fires have burned more than 27 million acres of land, according to the Canadian Interagency Forest Fire Centre. That broke Canada’s previous record for an entire year, set in 1989, when more than 18 million acres burned. And there’s plenty more time to add to the record.

The center warned that the “potential for emerging significant wildland fires is high to extreme.”

Flooding in Vermont

A man set up a fishing rod as he and his friends took to the flood waters via canoe in downtown Montpelier. Jessica Rinaldi/Globe Staff

The World Meteorological Organization this week said heavy rains and flooding had caused severe damage and loss of life in several parts of the world, including Korea, Japan, India, and China.

The UN agency also noted the recent flooding in the Northeastern United States, including in New England, where Vermont saw widespread flooding last week.

In Montpelier, where the Winooski River came over its banks, the 9.95 inches of rain reported there by Friday was the most ever reported in July, easily topping the previous record of 8.0 inches, even though the month isn’t over yet. Nearly 7 inches of this month’s rain fell during last week’s storm alone.


“As the planet warms, the expectation is that we will see more and more intense, more frequent, more severe rainfall events, leading also to more severe flooding,” Stefan Uhlenbrook, Director of hydrology, water and cryosphere at WMO, said in a statement.

Sabrina Shankman of the Globe staff contributed to this report. Material from Globe wire services and major media outlets was used in this report.

Martin Finucane can be reached at martin.finucane@globe.com.