paper link: https://www.science.org/doi/10.1126/science.adt2981

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Editor Summary:

Body size and metabolic rate are intertwined, a factor that is especially important to understand with regard to animals that live in aquatic environments, where heat loss is related to water temperature. Payne et al. developed a method to estimate routine metabolic rate based on measures from tagged fish, and combined the estimates with published respirometry rates to create a dataset spanning the entire body size range of extant fishes. Using these data, the authors found a scaling imbalance between heat production and loss that affects especially large, mesothermic fishes in warm waters. This imbalance both explains the distribution of these fish in cooler waters and suggests a special sensitivity to warming waters. —Sacha Vignieri

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Abstract:

Body size and temperature set metabolic rates and the pace of life, yet our understanding of the energetics of large fishes is uncertain, especially of warm-bodied mesotherms, which can heavily influence marine food webs. We developed an approach to estimate metabolic heat production in fishes, revealing how routine energy expenditure scales with size and temperature from 1-milligram larvae up to 3-tonne megaplanktivorous sharks. We found that mesotherms use approximately four times more energy than ectotherms use and identified a scaling mismatch in which rates of heat production increase faster than heat loss as body size increases, with larger fish becoming increasingly warm bodied. This scaling imbalance creates an overheating predicament for large mesotherms, helping to explain their cooler biogeographies. Contemporary mesotherms face high fuel demands and overheating risks, which is a concern given their disproportionate demise during prior climate shifts.

Is that sharks are an ancient species and they’ve survived way warmer oceans even relatively recently.

For example the Medieval Warm Period Sargasso Sea surface temperatures were 1°C warmer than 400 years ago, and Pacific Ocean water temperatures were 0.65°C warmer than the decades before.

- if everyone on the entire planet went 100% vegan from tomorrow, will carbon emissions really go down by 60%?

I don’t see a way out except for stratospheric aerosol injection.

But this is the world now, there will only be more stories like this, and so I'm not turning away from it any further. The world becomes less beautiful, less rich, less full every year.

I do volunteer, donate, and advocate and I won't use my extreme pessimism as an excuse not to engage. But in private, I mourn what is coming with little hope for substantial reduction in harm. If anything, those with power seem upset that we're not doing more to fasttrack catastrophe - if it's going to happen, may as well be the one to profit from it as much as possible before you're dead, the thinking seems to go.

A lot of the changes to the waters is well outside human control... there's a huge balance of factors at play from the earth, moon and sun. We don't control these things... and to what impact we can/do, I'm not sure that anything we might do may not have unintended consequences that are materially worse.

We can definitely do some things, but the level of internalized and externalized guilt that people in and outside these discussions seem to carry and put on others isn't at all healthy in and of itself.

They will move to different locations like they always have been for the past 400 million years. Sharks are older than trees, they can adapt to climate change better than anything alive right now.

For example, something is red, you touch it, get burned. You won’t touch it again.

Environmental harm unfortunately is precisely the opposite. Consequences arise on a very long arc, in some cases beyond even our lifetimes. We register problems like this only intellectually, and even that becomes clouded with politics.

So the problem is kind of inevitable unfortunately.