You can find more posts on climate change science, policy, and news on Climate 411.
OK, so I’m one day late for Earth Day because I was swamped at work yesterday ... on the plus side, after PA, people might have more time to check out a non-primary diary!
In honor of Earth Week, this is a bigger-picture diary than my usual offering. Instead of covering a single topic as I normally do, I thought I’d give an overview of some of this week’s developments in climate change research.
Follow me over the fold for the latest on ocean acidification, Greenland’s glaciers, and the costs and opportunities from fighting global warming.
First off, Environmental Defense Fund would like to wish you Happy Earth Day!
And now on to some of this past week’s big stories:
Ocean acidification and calcifying organisms
Basic theory suggests that calcifying organisms will have a harder time forming shells as CO2 levels rise, because of "ocean acidification". The surprise this week was a study that found that at least one shell-forming marine species – the coccolithophore E. huxleyi -- might increase as CO2 levels go up. Scientists aren’t sure why the results were so different from other studies. Possible explanations include genetic variation within species (previous studies with E. huxleyi found opposite results) and experimental set-up (the latest study bubbled CO2 into the water rather than controlling pH with acid).
What is certain is that the effects of ocean acidification are going to be complex. Scientists are just beginning to study the phenomenon and its effects on marine life. To date, only a handful of species have been studied – never mind the effects on the entire marine food web! – and most of that research has been in tightly controlled lab conditions.
For more:
- A
report about ocean acidification from the Royal Society
- The latest study showing increased growth of
E. huxleyi (here’s
the summary; $ubscription required for the full article)
- An overview of recent research with an emphasis on the latest study (again,
the summary; $ubscription required for the full article)
- Research on acidification effects on
reef-building algae
- A
Science magazine
summary of recent acidification research presented at the latest AAAS annual meeting
Greenland’s glaciers
Several years ago, scientists working in Greenland observed water pouring down cracks and tunnels in the ice. (These holes, called
moulins, can drain large surface lakes at a rate of about four Olympic pools per second.) The scientists hypothesized that once the water reached bedrock, it could act as a lubricant and accelerate glaciers’ flow toward the sea. (This has been nicknamed the "Zwally effect" after the NASA scientist who led the study.)
Two studies out in Science Express this week confirmed that meltwater does indeed reach the bedrock and enhance glacial movement. However, there was (relatively) good news. When the team looked at movement along the whole glacier, they found that the Zwally effect could be quite large in inland areas, but that outlet glaciers at the coast – where ice actually moves into the sea – were "relatively insensitive" to the phenomenon. Their conclusion was that the Zwally effect "likely will have a substantive but not catastrophic effect on the Greenland Ice Sheet's future evolution".
Still, many of Greenland’s outlet glaciers have accelerated in recent years. If the Zwally effect isn’t to blame, what is? The leading hypothesis for now is what’s called "back-stress reduction" or the "Jakobshavn effect". In this case, as the coastal edge of an outlet glacier thins, it decreases some of the friction against the bedrock, allowing the glacier to slide forward more quickly.
Scientists still have a ton to learn about glacial dynamics. For example, which glaciers are more affected by the Zwally effect, back-stress reduction, or other factors? Can we model these effects to predict future changes? In the meantime, one thing remains clear: Greenland’s glaciers are accelerating, contributing to sea level rise.
For more:
- A
NASA press release describing the Zwally effect.
- A
Science news article describing the two latest papers about Greenland’s glaciers. ($ubscription required for full article, sorry)
- The two latest studies
confirming the Zwally effect and measuring
movement along the entire glacier. ($ubscription required for full articles)
- A
RealClimate post about Greenland glacier acceleration.
Messages of hope: the costs and opportunities from fighting global warming
One of the arguments that opponents of climate change legislation often make is that it will cripple the economy. This week, my colleagues Nat Keohane and Peter Goldmark released a report debunking this flawed claim.
Their report compiles the results of lots of different economic models and shows that the cost would be less than 1 percent of U.S. GDP in 2030. Here’s another way of looking at it: Every single model projects robust economic growth – more than doubling by 2030. Under business-as-usual, the economy reaches that benchmark in January 2030. With an emissions cap, we’d have to wait until... April.
It’s a great report, it goes nicely with a book ("Earth: The Sequel") written by Environmental Defense Fund president Fred Krupp and journalist Miriam Horn. They highlight some of the exciting innovations in energy technology that are just waiting for the right legislative signals that would bring these and other clean technologies into the market. Global warming is a huge, urgent problem and it is easy to become despondent. The book is a welcome message of hope and opportunity.
Please remember, I wear a science hat here on DailyKos, so if you’d like to discuss the book or the economics report, head over to Climate 411. Fred’s already put up a post about his book. I know Nat is working on one that describes his report, so stay tuned for that.
Happy Earth Week!