You can find more posts on climate change science, policy, and news at Climate 411.
It’s Friday afternoon, and time for a look back over the week. There were two studies that jumped out at me. The first study says it all in its title.
- "One-third of reef-building corals face elevated extinction risk from climate change and local impacts."
- The effects of climate change could hit U.S. water supplies harder than scientists previously thought.
Coral Reefs
Coral reef ecosystems are in trouble. Global warming is causing more frequent coral bleaching events around the world, and marine biologists are increasingly concerned about ocean acidification. Locally, individual reefs face threats such as coastal development, water pollution, over fishing and coral mining.
The ecosystem picture is clear – but what about individual species? Last night, Science Express published an assessment of the status of individual reef-building coral species.
The authors used data on population size and geographic range to classify species’ extinction risk. (Specifically, they followed IUCN Red List Categories and Criteria. The greater the decline in a species’ population size or geographic range, the greater its risk of extinction.)
They had enough data to classify 704 coral species; they found that 231 species had an elevated risk of extinction. This is an enormous change from 10 years ago, when only 13 species were considered in trouble.
As the authors say, the results "emphasize the widespread plight of coral reefs and the urgent need to enact conservation measures". Those conservation measures are absolutely critical in the fight against climate change, because marine biologists believe that if we can reduce direct local threats, we can help corals become more resilient to climate change.
More information on coral reefs
- A summary of an earlier
NOAA study on U.S. coral reefs
- 2008 is the
International Year of the Reef
-
11th International Coral Reef Symposium, held this week in Florida
Western Water Supplies
Water management is already a complex and contentious issue, particularly in western states where millions of Americans depend on snowmelt for hydropower, irrigation, and drinking water. I've written previously about how global warming is changing the timing of spring snowmelt and shifting the Southwest to a drier climate.
There's a new study (Rauscher et al, in press in Geophysical Research Letters) that suggests the effects could be worse than previously thought.
Scientists use computer models to investigate the likely effects of global warming on spring snowmelt. Previous studies indicated that by 2100, snow could begin melting about a month earlier than it does today. The new study uses a model that captures the topographical complexity of the American West more accurately than previous versions. It does a pretty good job simulating current trends in snowmelt timing, which gives modelers more confidence in its ability to simulate future patterns. (This is a model-testing technique known as hindcasting.)
When the scientists ran the higher-resolution model in a business-as-usual scenario (i.e., unchecked global warming pollution), it showed a much more pronounced snowmelt response than in the earlier models. For example, in the Pacific Northwest, snow started melting more than two months earlier than it does today.
Our infrastructure and our water use habits have developed based on historical patterns of water flow. Those flows are going to change, and the latest research suggests that previous warnings haven’t been quite strong enough.
More information on global warming and water
Environmental Defense Fund's Center for Rivers and Deltas
Saving Energy by Saving Water - and Vice Versa
EDF has a water blog, On the Water Front