Waters off the coast of Florida as hot as a hot tub, and more heat news from around the world

The water temperature off southern Florida has been about 38 C two days in a row: that's as hot as a hot tub, as hot as the maximum recommended heat for a baby's bath, and hotter than what's usually recommended for a pregnant woman.

It's also, meteorologists say, possibly the hottest seawater ever measured.  

The U.S. National Oceanic and Atmospheric Administration (NOAA) says weather records for sea water temperature are unofficial and there are certain conditions in this reading that could disqualify it for a top mark, but the initial reading on a buoy at Manatee Bay hit about 38.4 C Monday evening. The night before, it was 37.9 C.

"This is a hot tub. I like my hot tub around 100, 101, [37.8, 38.3 C]. That's what was recorded yesterday," said Yale Climate Connections meteorologist Jeff Masters. 

If verified, the Monday reading would break the prior record set in the waters off Kuwait three summers ago, 37.6 C.

The consequences for sea corals are serious.

Bleaching — which doesn't kill coral, but weakens it and can lead to death — occurs when water temperatures exceed the low 30s.

This all comes as sea surface temperatures worldwide have broken monthly records for heat in April, May and June, according to NOAA. Temperatures in the North Atlantic are off the charts, up to 6 C warmer than normal in some spots near Newfoundland, University of Miami tropical meteorologist Brian McNoldy said.

From cacti dying in the U.S. to chicks leaping from nests to save themselves from the heat in Europe, here's a roundup on the latest effects of climate change worldwide.

In the U.S.: Could the Phoenix weather break? (Only 42 C on Monday)

This counts as a break for Phoenix, Ariz.

The fifth-largest city in the U.S. has hit 43.3 C for almost four weeks, but meteorologist Isaac Smith, of the U.S. National Weather Service in Phoenix, said the high is expected to be 42.2 C by next Monday.

Before this year, the longest stretch of days where temperatures reached 43 was 18, in 1974, said Erinanne Saffell, Arizona's state climatologist.

Phoenix last got measurable precipitation on March 22.

"In the early 1900s, Phoenix had about five days, on average, every year that were 100 degrees or higher," Saffell said. "Now we're five times that number on average."

A symbol of the U.S. West is dying in that heat.

Arizona's saguaro cacti are leaning, losing arms and, in some cases, falling over. Summer monsoon rains the cacti rely on have failed to arrive, testing the ability of the 12-metre giant to survive in the wild.

In Oregon, a fire that started over the weekend has burned dozens of homes and caused area residents to lose 911 service and internet. The Oregon State Fire Marshal said the fire destroyed 43 residences near the town of Bonanza. Law enforcement officials say the blaze may have started on property being used to grow marijuana illegally.

In Canada: Salmon fishing rivers feeling the heat in N.L. 

Dozens of salmon fishing rivers are limited to "morning angling only" in Newfoundland and Labrador by the Department of Fisheries and Oceans, which cited extremely high water temperatures and a lack of rainfall in a statement on Tuesday.

Temperatures of over 20 C are being reported at rivers across the province, according to Craig Purchase, a professor of fish biology at Memorial University.

Purchase said water temperatures surpassing 22 and 23 C have been seen before — especially in the past few years — but seeing those reported temperatures for an extended period is concerning.

Anglers who have shared photos with CBC News have reported dead salmon washing up at Lower Falls in Dunville, N.L.

"This is entirely predictable. You would expect salmon to die under these conditions," Purchase said.

There are currently heat warnings in four provinces: Saskatchewan, Ontario, Nova Scotia, and Newfoundland and Labrador.

In Europe: Fires throughout the south, including Game of Thrones stand-in Dubrovnik

Major fires raging in parts of Greece and in other Mediterranean countries advanced Wednesday, causing additional deaths, destroying homes and threatening nature reserves during a third successive wave of extreme temperatures.

New evacuations were ordered overnight on the islands of Corfu, Evia and Rhodes, where thousands of tourists were moved to safety over the weekend. Authorities said the charred remains of a missing farmer were found in southern Evia — a discovery made following the death of two Greek firefighting pilots, who were killed in a crash during a low-altitude water drop.

The summer wildfires have struck countries across the region, including Algeria, where at least 34 people were killed in recent days.

In Italy, the bodies of two elderly people were found in a home that had been consumed by flames near the Palermo airport, on the island of Sicily, which had been closed temporarily because of the encroaching flames, according to Italian news reports. Freak storms in the north of the country also left two people dead on Tuesday from falling trees.

In Croatia, a wildfire was burning several kilometres away from the famous walled town of Dubrovnik, in the country's south along the Adriatic Sea coast, where water-dropping planes and more than 100 firefighters held back the blaze before it reached houses overnight. The medieval stone city, a protected heritage site and Croatia's best-known tourism destination, was the main stand-in for the Game of Thrones city of King's Landing.

In Portugal, more than 500 firefighters continued to combat a blaze close to Lisbon. The fire forced the evacuation of 90 people from their homes, along with 800 farm animals.

In Switzerland, sparrows and swifts have arrived in droves at a centre treating distressed birds after soaring temperatures caused them to dehydrate, with chicks even leaping from their nests in a desperate attempt to evade the blistering heat.

The Centre Ornithologique de Réadaptation on the outskirts of Geneva admitted around 30 birds a day, many with heat-related ailments, when temperatures soared past 30 C this month.

"This is not an issue we had before," said ornithologist Patrick Jacot, referring to the scores of birds adversely affected by the heat.

Birds that nest in hollow places, in anything from eaves to mailboxes, are particularly vulnerable. Their nesting grounds— sometimes metallic — overheat, causing hatchlings to jump in dramatic and sometimes lethal fashion.

"Birds will jump out on their own when they are not at all old enough to leave the nest," said biologist Fanny Gonzalez, a specialist in biodiversity conservation who works at the centre. "They will fall a few metres, end up on the equally hot asphalt and be completely helpless there."

In northern Germany, scuba divers used hand trowels to dig up emerald green seagrass shoots, complete with roots, from a dense underwater meadow, then headed out the next day to a barren area farther north to replant them.

One diver holds a line, and the other uses it to navigate the murky waters and swim around him.

They hope this painstaking work, part of a new project that trains local citizens to restore seagrass meadows in the Baltic Sea, can help tackle climate change.

The meadows act as vast natural sinks that can store millions of tonnes of carbon, but they have reduced sharply over 
the last century due to worsening water quality, scientists say.