24 May 2012

Winter 2010 | Momentum | Institute on the Environment | University of Minnesota

A Survival Guide to Geoengineering

Despite its potential to trigger conflict, geoengineering will likely be part of the global response to climate change. Be prepared.

By Jamais Cascio

Geoengineering

Illustration: Mark Thoburn
The idea of geoengineering has been around for some time—often imagined in science fiction and futurist tomes as giant orbiting mirrors blocking the sun. But as the dangers of global warming have become more evident, while efforts to reduce carbon emissions continued to stall, the concept has moved from the scientific fringes to the mainstream.

The tumultuous outcome of the Copenhagen summit drives home two clear facts: The political struggles around how we respond to global climate disruption are enormously complex—and the resulting delays are bringing us dangerously close to disaster.

This disaster may not unfold in the way we expect. Accelerating changes to the global climate may render even the most aggressive carbon reductions insufficient. But there’s a good chance that the action taken will be in the form of geoengineering, or the intentional modification of geophysical systems to reduce the impacts of climate change.

However, the clashes around geoengineering will make COP15 look amicable. Done carelessly,geoengineering could cause unintended environmental damage. It could also undermine the health and security of millions of people, and drive political wedges between powerful nations. Geoengineering could even push us to the brink of war.

While we know geoengineering would be enormously risky, we’re likely to try it anyway. We can’t eliminate the risks entirely, but if we act wisely, we can make the risks more manageable. Here, I lay out a few ideas for making sure that any geoengineering efforts are done in ways that reduce the risks of both environmental harm and political conflict.

Risky Business

The idea of geoengineering has been around for some time—often imagined in science fiction and futurist tomes as giant orbiting mirrors blocking the sun. But as the dangers of global warming have become more evident, while efforts to reduce carbon emissions continued to stall, the concept has moved from the scientific fringes to the mainstream.

Nobel Prize-winning scientists like Paul Crutzen have openly endorsed research into geoengineering—not as a substitute for carbon reductions, but as a stopgap measure to prevent runaway catastrophe. Reports from respected scientific bodies (such as the U.K.’s Royal Society and the American Meteorological Society) have cautiously endorsed research into geoengineering.

The concept is even gaining some popular visibility, appearing in The Atlantic Monthly and the 2009 pop-economics book SuperFreakonomics. It was also the focus of an article I wrote for the Wall Street Journal.

The current version of geoengineering has dispensed with the space mirrors, adopting a variety of more down-to-earth measures. One proposal would seed the oceans with iron to trigger algae blooms, which pull carbon dioxide from the atmosphere (initial experiments were unsuccessful, but research continues). Another would cool the atmosphere through the use of massive vortexes, mixing colder air from high up with the warmer air near the surface.

The plan that has received the most attention is one where megatons of sulfur dioxide particles would be pumped into the stratosphere, causing a slight dimming of incoming sunlight, cooling the planet by a few degrees. As outlandish as that might sound, it’s an idea that has worked in nature—it’s one of the side effects of a volcanic eruption.

As the most feasible geoengineering proposals do nothing about rising carbon levels, they aren’t considered solutions for global warming. They’re just temporary fixes meant to delay the worst heat-related impacts while the world completes its sluggish transition from fossil fuels. There are currently no known large-scale geoengineering projects underway. Yet, a growing number of scientists support the idea of researching ways to use geoengineering in a global warming crisis.

The appeal of such plans is obvious, as is the environmental risk. Nations desperate to do something about imminent climate disaster would readily embrace mechanisms to slow the disaster’s onset. But the sheer complexity of the ocean-atmosphere system almost guarantees that interventions on this kind of scale will have unexpected and unwanted consequences.

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Yes, it's that time... geoengineering is starting to seem inevitable, time to learn the ins and outs.

10 May 2012

Arctic Ocean is a Potent Methane Source Too | Mother Jones

Arctic sea ice: NOAA

Arctic sea ice: NOAA 

We've known for a while that a melting Arctic is likely to be a big methane producer, and that methane is a potent greenhouse gas. Until recently we thought the primary sources of Arctic methane were from:

  1. Melting tundra
  2. Melting marine sediments (like gas hydrates)

Now a new paper in Nature Geoscience reports the Arctic Ocean is itself a source of atmospheric methane. Here's how this scientific riddle got cracked. From NASA's Earth Observatory:

During five research flights in 2009–10, [researchers] measured increased methane levels while flying at low altitudes north of the Chukchi and Beaufort Seas... The methane level detected during the flights was about one-half percent higher than normal background levels.
But where was the methane coming from? The team detected no carbon monoxide in the atmosphere, which would have been a signature of methane coming from the human combustion of fuels. And based on the time of year, the location, and the nature of the emissions, it was unlikely that the methane was coming from high-latitude wetlands or geologic reservoirs.

 Thawing on East Siberian Arctic Shelf: Zina Deretsky, National Science Foundation

Thawing on East Siberian Arctic Shelf: Zina Deretsky, National Science Foundation 

The researchers eventually pinpointed the source: the Arctic Ocean. But not just any part of the Arctic Ocean. From the paper:

"While the methane levels we detected weren't particularly large," says lead author Eric Kort, "the potential source region, the Arctic Ocean, is vast. So our finding could represent a noticeable new global source of methane."

We further show that high methane concentrations are restricted to areas over open leads and regions with fractional sea-ice cover. Based on the observed gradients in methane concentration, we estimate that sea–air fluxes amount to around 2 mg d−1 m−2, comparable to emissions seen on the Siberian shelf. We suggest that the surface waters of the Arctic Ocean represent a potentially important source of methane, which could prove sensitive to changes in sea-ice cover.

To put that into perspective, the East Siberian Arctic Shelf is leaking an amount of methane comparable to all the methane from the rest of the world's oceans put together. In the schematic above, you can how its permafrost is highly porous, allowing methane stored under to burst through cracks into the atmosphere. 

According to the new research, now we're talking about a rapidly de-icing Arctic, with methane bursting through its ice cracks, capable of contributing hella big methane to the atmosphere. Talk about a tipping point.

No one's yet sure how the methane is produced, but lead author Eric Kort suspects biological productivity in Arctic surface waters may be the culprit. "It's possible that as large areas of sea ice melt and expose more ocean water," he says, "methane production may increase, leading to larger methane emissions."

 

 

The video condenses the rapid changes underway in the Arctic into two minutes (though prior to the new evidence on methane production from the Arctic Ocean).

The paper: 

  • E. A. Kort, et al. Atmospheric observations of Arctic Ocean methane emissions up to 82° north. Nature Geoscience. DOI:10.1038/ngeo1452 

 

Nicely done job of presentation. You may wish to see the original for a slightly better view.

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