BEAR4NATURE asks: Assuming that future El Niño events are likely to become more frequent and more intense, primarily caused by additional warming of the Pacific Ocean due to human-caused climate alteration, is it feasible that most or all current oceanic lifeforms might eventually die off over centuries or even decades?

Jon says: I haven’t heard anyone suggest the total eradication of all lifeforms in the ocean. Even in the previous five great waves of extinction, some forms of ocean life have survived. In fact, I would guess marine life is usually less vulnerable than terrestrial life. But there are unprecedented threats right now in the forms of heat acidity, destratification, a weakening of the biotic pump and the slowdown of currents.

For me, the most shocking statistic of the year is about the heat content of the oceans, which has doubled in the past two decades. That is because the oceans absorb 90% of the excess energy left in the Earth System as a result of human-caused climate disruption (the burning of oil, gas and coal, which has a “greenhouse effect” that prevents energy from escaping back out into space.

The scale of the energy build-up in the oceans is what knocks me sideways. As I wrote in an earlier story:

“The scientist John Abraham has previously calculated the accumulation of energy in terms of the explosive power of the Little Boy atomic bomb that devastated Hiroshima in 1945. In 2020, he observed that the amount of heat being added to the oceans was equivalent to about five Hiroshima bombs of energy every second. By 2022, this had gone up to seven Hiroshimas every second. Last year, the WMO figures suggest, it was closer to 11 Hiroshima explosions per second.”

Imagine all that extra heat! Some of it accumulating in the depths for centuries. Some of it vomited back out into the atmosphere in the form of an El Niño.

How can ocean life not be affected by that? We know that coral reef systems are dying (or as one expert described it to me “flickering out like lights across the world”) but there must be so many other impacts that cannot yet grasp because humans know almost less about the deep than we do about outer space.