Scientific American June 2013
Climate Science: Storm of the Century, Every Two Years (p 58)
To protect New York City from the increasing number of flooding events expected in the next century—similar to Hurricane Sandy—the city needs to consider a costly and invasive option: permanent evacuation of communities in the lowest-lying areas and massive barriers around the city that will cost billions of dollars. In a feature published in this month’s Scientific American, Mark Fischetti discusses these options as well as other difficulties East Coast cities from Massachusetts to North Carolina will face as weather patterns shift due to climate change.
Flooding and other “extreme climate events” on par with Sandy are forecasted to hit the East Coast as often as one every two years by the end of the century. In New York, scientists, engineers and city officials have been looking at various measures and large-scale projects that would protect the city. Fischetti reports that many engineers and climate scientists believe that the only way to adequately protect the region against 11-foot water surges like those seen in Sandy, is massive flood barriers that would cost $10 billion to $20 billion. However, the report that will be delivered to Mayor Michael Bloomberg by the end of May, is unlikely to recommend this promising option because of its steep cost.
Moreover, the report will likely be missing a few other difficult recommendations, such as ending federal subsidies for flood insurance and abandoning low-lying communities along the shore. These decisions, though tough to make, are necessary for long-term solutions to the five feet of sea-level rise that the latest climate science predicts by 2100.
Science Agenda: Do Not Reanimate (p 12)
A project to revive long-gone species, such as woolly mammoths, has been garnering a lot of media attention. But such “de-extinction” efforts, which would utilize cloning, sequencing and other biotechnology feats to re-create extinct species from their ancient DNA, should not be pursued, the Editors of Scientific American argue in this month’s Science Agenda.
Instead, we should focus our financial and intellectual efforts to save not-yet-extinct species, which include some 20,000 species according to a 2012 report from the International Union for Conservation of Nature. These animals are currently in danger of going extinct due to human activities rather, and deserve more attention than species wiped off the earth hundreds, or even thousands, of years ago.
Life Science: Tiny Plants That Once Ruled the Seas (p 40)
The dramatic explosion in marine animal diversity 250 million years ago may have been due to the shifts in the abundance and types of marine phytoplankton. A feature article by Ronald Martin and Antonietta Quigg in this month’s Scientific American unravels the series of events which led to the emergence of new groups of predatory fish, mollusks and crustaceans—diversification that has previously been attributed to sea-level fluctuation and other physical factors.
The availability of micronutrient in the oceans appears to have fueled the growth of phytoplankton—which form the bottom of the food chain. Martin and Quigg believe that the evolution of these tiny plants fueled a ripple effect upwards on the food pyramid, from nutrient-rich red algae, to the zooplankton, to larger animals, resulting in ample food to sustain diversification of bigger organisms with higher metabolic rates.
There are several lines of evidence to support the hypothesis. While the ocean diversity was proliferating, there was a concurrent spread of forests on land. The increased weathering from land plants—decaying leaves and roots and soil run-offs—resulted in an increase in nutrient seeping into the oceans. Isotope studies—which document nutrients changes from million years ago—of fossilized shells confirm such a change in ocean composition. Given how important these microscopic organisms were in the biosphere millions of years ago, the authors emphasize the need to consider how changes to the environment, such as we are experiencing right now, will affect phytoplankton abundance and thus marine animal diversity in the future.
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