Global spate of weather extremes precedes risky summer

Why it matters: Unrelenting heat in Southeast Asia, flooding in Brazil and Texas and other events provide a foreboding preview of the summer season and match scientific expectations of a warming climate.

• The extremes that have been occurring this spring are happening in a world that has seen global average temperatures increase by about 1.2°C (2.16°F) compared with preindustrial levels.
• With most climate models and researchers projecting that warming will exceed 2°C above preindustrial levels, these may be relatively tame previews of Earth's future.

Zoom in: Multiple countries have set national monthly temperature records during May, with all-time records falling as well.

• Nearly all of Mexico has recently been in the grip of an area of high pressure aloft, also known as a heat dome, that has locked hot and dry weather in place.
• The country's hottest temperature record for the month of May fell in Gallinas last week, according to meteorologist Etienne Kapikian of Meteo France.
• In a post on X, Kapikian reported the temperature hit 51.1°C (124°F), setting new Mexican and North American monthly records and reaching just 0.9°C (1.62°F) shy of Mexico's all-time highest temperature for any month.
• Mexico's heat wave is expected to continue through at least the next week.

What they're saying: "World climatology is being rewritten with this brutal heat wave which has no end in sight," records tracker Maximiliano Herrera said on X.

The big picture: Thailand, China, Myanmar, Japan, Cambodia, Vietnam, the Philippines, Pakistan and India have been in the throes of intense heat since March or April.

• Temperatures as high as 122°F (50°C) are possible in the next two weeks as heat approaches a peak in Pakistan, according to Herrera.
• India and China are also forecast to see temperatures climb further. China already saw its warmest April on record.
• Parts of Myanmar have set all-time hottest temperature benchmarks, and Laos saw its hottest temperature as well; Vietnam also broke monthly and all-time records during April.
• The AP reported that 70 countries or territories broke heat records in just the first five days in May.

Stunning stat: The U.S. hasn't been immune, either. La Puerta, Texas, tied the state's record for the hottest temperature in May with a high of 116°F on May 9.

• This was one of the hottest temperatures observed in the country so early in the season.
• Although less attributable to climate change, a 16-day surge in severe weather across the U.S. led to at least 267 confirmed tornadoes in 19 states, according to the Storm Prediction Center.
• And heat plus drought already jump-started Canada's wildfire season, sending smoke into the U.S.

Between the lines: Heat waves are the type of weather event that scientists most confidently attribute to climate change; as global average temperatures increase, the probability of extreme heat increases dramatically.

• One rapid attribution study found that a heat wave that struck the Sahel and West Africa at the end of March into early April would not have happened without human-caused climate change.

• This heat wave affected countries including Senegal, Mali, Nigeria and Burkina Faso.
• Some of these same countries are seeing fierce heat again now.

Threat level: A combination of record-warm oceans, an atmosphere that still reflects the influence of an El Niño in the tropical Pacific Ocean, and long-term warming from the burning of fossil fuels are all likely contributing to recent — and upcoming — extremes.

• In addition to the heat, climate change also affects precipitation, with heavy downpours becoming more frequent and severe.
• Parts of the Houston metro region received nearly 2 feet of rain in just a couple of days in early May, yielding damaging flash and river flooding.
• The situation has been far worse in southern Brazil, where tens of thousands of people have been displaced and dozens killed from floods resulting from days of downpours across the state of Rio Grande do Sul.
• The Porto Alegre metro area, home to about 4 million people, saw its international airport disappear beneath floodwaters, along with vast swaths of homes and businesses, after two months' worth of rain fell in a few days.

What's next: Computer model projections for the Northern Hemisphere show widespread warmer-than-average conditions this summer, with a few exceptions.

• One of the biggest concerns for the summer, in addition to heat waves, is an extremely active Atlantic hurricane season, one that is perhaps on par with the busiest seasons on record.
• This would be due to a combination of record-warm Atlantic Ocean waters and a developing La Niña in the tropical equatorial Pacific Ocean.