Saturday round-up: Jones talks, CO2 threatens plankton, and Greenland glaciers melt

Sediment core spanning the Paleocene-Eocene green-house warming event

Sediment core spanning the Paleocene-Eocene green-house warming event 55 million years ago. The sharp transition from carbonate-rich shell sediments (grey-white) to pure clay (red) indicates the dissolution of carbonates due to ocean acidification. Photo by Daniela Schmidt on board the JOIDES Resolution Drill Ship.

“Climategate scientist Phil Jones ‘considered killing himself’”. “Climate emails cannot destroy proof that humans are warming the planet”. “There has been no global warming since 1995”.

The scientist who provided the ammunition for escalated attacks on global warming science spoke out this week for the first time since his emails were leaked in November. If you saw any of the reports about the University of East Anglia’s Phil Jones, what you think he said would depend on where you saw it. Each of the headlines above is from a UK news organisation taking a different angle on his comments: guess which publication they’re from if you like, using the commenting tool at the end of this post.

A straight transcript of Jones’ interview with the BBC is available here. He does indeed concede that there has been no statistically significant warming since 1995, but notes that it’s a close run thing. “Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods,” Jones says. So, if you take a 30 year period from 1979, there has been statistically significant warming since then. Meanwhile, although there has been a cooling trend since 2002, Jones points out that too is not statistically significant.

An interesting aspect of the coverage is that Jones’ infamy has actually given him a chance to try and explain climate change. You might argue that the fact his conduct is being investigated makes him hard to trust, but there are few more well-known climate scientists today.

If you find the statistical significance of temperature changes too vague, here’s a fairly clear statement for you: CO2 emissions are set to create the most rapid acidification of the ocean for 65 million years. The rate of change is likely to exceed plankton’s ability to adapt to it, says a paper published online this week in Nature Geoscience. This could have serious consequences for the sea, because plankton helps to reduce CO2 concentrations by making shells out of it, which eventually become minerals.

Andy Ridgwell and colleagues at the University of Bristol compared the current situation with a greenhouse warming event known as the Palaeocene-Eocene thermal maximum (PETM) 55.5 million years ago. They gained their historical data on CO2 levels by looking at minerals dating back to that period. Their model of the future situation is based on how much CO2 would be produced if humanity burnt around half of the available fossil fuel supplies. Oceans currently absorb about a quarter of the CO2 released into the atmosphere, acidifying the ocean.

Some deep-sea plankton became extinct during the ancient greenhouse warming period, Ridgewell’s team writes.“The occurrence of widespread extinction of these organisms during the PETM greenhouse warming and acidification event raises the possibility of similar extinction in the future.”

Two further Nature Geoscience papers this week have found that warmer waters around Greenland are speeding the movement of its glaciers into the sea. In one, Fiamma Straneo and a team of Canadian and US researchers studied the temperature of the water thoroughly for the first time. The found evidence of a fast and direct pathway taking warmer water from the North Atlantic to Greenland’s southeast and west coasts.

In the other, Eric Rignot and a US team discovered that glaciers in West Greenland are melting 100 times more rapidly at their end points beneath the ocean than they are at their surfaces. Rignot’s team note that the amount of ice-sheet lost overall from Greenland tripled from 1996-2007. Over half of that loss is from glacier acceleration, with the glaciers slipping into the sea and forcing up sea levels faster. “Glacier acceleration is a significant response to climate warming,” the scientists write. The undersea melting that Rignot and his colleagues observe plays an important part in detaching the glaciers from the sea bed, allowing them to move faster.

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