Climate Change Briefs: Death by Heat on Land and at Sea

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A man holding a cross and a Bible preaches about Christianity backdropped by the Royal Exchange, back center, and the Bank of England, at left, during England's second coronavirus lockdown in the City of London financial district of London, Wednesday, Nov. 18, 2020
Holding a cross and Bible, preaching by the Royal Exchange and Bank of England during England's second coronavirus lockdown, Nov. 18, 2020Credit: Matt Dunham,AP

Heat waves caused a record 2,556 excess deaths in Britain this summer, the government estimated last Thursday. Reuters reported that from June to August, the United Kingdom suffered not one but a number of record-breaking heat waves. However, researchers speculate that the pandemic may have exacerbated matters by deterring people with heatstroke from seeking hospital care, lest they catch the virus.

Apropos the coronavirus, the Red Cross organization noted in an umbrella report “Come Heat or High Water” that there’s no vaccine for climate change. The U.S. passed 12 million COVID-19 cases – known cases, that is – on Saturday, which is serious. But unsurvivable conditions on the planet will be even more serious.

100% of coral will be in trouble this century

Most coral survive through a symbiotic relationship with zooxanthellae (algae that live within the coral tissues). Coral bleaching happens when the algae partner dies. If emissions continue unabated, 100 percent of all coral will suffer severe bleaching sooner, not later, in this century, warns a new United Nations report by lead author Ruben van Hooidonk of the NOAA’s Cooperative Institute for Marine and Atmospheric Studies. When will annual severe bleaching begin? By 2034, it seems, nine years earlier than had been projected as a global average for the worst-case scenario.

Fish swimming over a patch of bleached coral in Hawaii’s Kaneohe Bay off the island of Oahu.Credit: AP

And under the not-worst scenario? Annual severe bleaching is anticipated by 2045, assuming the present climatic trajectory persists. Fulfilling the Paris Agreement will be too little too late, the report mourns. Some reefs will be affected sooner, some later. If the conditions that killed the algal partner (generally, heat and/or acidification) subside within days, the algae come back and all is well. If the bleaching persists, the coral dies. Polluting the water isn’t helpful either. What can be done? You know: cut back consumption massively, globally, period.

Trump in last-ditch effort to cause damage

In its death throes, the Trump administration is pushing dozens of anti-environmental laws weakening protections for birds, expanding Arctic drilling for the sake of America’s “energy leadership” and hamstringing future regulation of threats to public health, warns MarketWatch. “We’re going to see a real scorched-earth effort here at the tail end of the administration,” said Brian Rutledge, a vice president at the National Audubon Society. Some Joe Biden can reverse easily, others less so, as the seesaw in Washington continues to judder.

Help, kelp!

As suspected, kelp might help mitigate ocean acidification, a team reported last week in JGR Oceans – a little. Kelp can grow very fast, many inches a day, during which it intensively photosynthesizes, removing carbon dioxide from the seawater and adding oxygen. Good. Testing showed slightly less acidic water near the sea surface where kelp lives. Good. But the ameliorating effect didn’t extend to the seafloor where acidification is the most intense and where acid-vulnerable animals live. “One of the main takeaways for me is the limitation of the potential benefits from kelp productivity,” said lead author Heidi Hirsh, a Ph.D. student at Stanford’s School of Earth, Energy & Environmental Sciences.

Giant kelp (Macrocystis pyrifera).Credit: Claire Fackler/ CINMS/NOAA

Kelp is (a) not exactly a plant – it’s a heterokont – and (b) in trouble. Kelp forests once thrived in the cool shallows off North America, but since 2014 have been devastated by an extreme change in their environment. To wit: the extreme decline in populations of sea stars, which used to eat sea urchins, which eat kelp. Also, the kelp doesn’t appreciate the warming water. But don’t eulogize the giant seaweed just yet: National Geographic describes a multidisciplinary effort to save the “sequoia of the seas.” 

Juvenile Macrocystis pyrifera, Whaler's CoveCredit: Chad King / NOAA MBNMS

Amazon more resilient to dryness than thought

Rainforests are thought not to do well when rainfall diminishes i.e., to water stress. Models of climate change consider that increasing aridity diminishes photosynthesis rates in certain parts of the Amazon. But now a new observational study found that in very wet parts of the jungle, if anything, increased dryness of the air boosted photosynthesis. “As the trees become stressed, they generate more efficient leaves that can more than compensate for water stress,” reported Pierre Gentine, associate professor affiliated with the Earth Institute at Columbia University, and the team in Science Advances.

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