Climate Letter #1212

A new study sees a net speeding up of carbon release from the Arctic tundra regions.  There has been a long debate over the balance between increases of carbon storage due to vegetation growth and losses due to permafrost melting as the temperatures warm.  It is a difficult thing to measure.  These researchers found a new tool that shows the mean residence time of carbon in the topsoil, which goes through a seasonal cycle year after year and is easy to measure.  They are seeing more annual losses than gains, which is a concern because there is a vast amount of carbon locked into deeply buried permafrost which keeps supplying the carbon that is lost.  “But only a fraction of the 1,300 billion to 1,600 billion tons of carbon locked away in permafrost soils needs to escape to have climate impacts.”

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A new theory about the origin of the ‘Younger Dryas’ event 13,000 years ago (Washington Post).  This story is especially valuable because it has a clear description of the event itself, which is quite interesting, and the probable nature of its cause.  The exact details of its origin are mainly of interest to scientists while the rest of us can take some comfort in knowing it can’t be repeated on anything near the same scale.

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The way people think about climate change in the US is changing (The Guardian).  A long-running survey finds that 73% now see solid evidence of global warming and 60% believe humans are at least partly responsible.  Contemporary weather is a contributing factor and can be compared with earlier memories but for some reason (which is not fully explained) that kind of tangible evidence has much less meaning for Republicans than for Democrats.  Worries are now forming about the cost of mitigation.

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