Climate Feedback

Tipping points - those critical thresholds in a complex system where a small nudge can cause a catastrophic response - are perhaps the most fearsome threats to the Earth’s climate, but they also haunt ecosystems, financial markets, and even sufferers of medical conditions such as epilepsy and asthma. A fascinating review in Nature today (subscription) sketches out the mathematical patterns on which many of these instances seem to be based, and describes giveaway signs that might warn us to change course before the system tips.

One common warning sign, for example, is flickering between the pre-tipping point state and the post-tipping point state. In climatology, abrupt changes traced in records of the Earth’s past suggest the planet has regularly gone through tipping points, such as the sudden warm-ups that change glacial periods into deglaciations. Earlier this year researchers reported in Nature Geoscience that rapid flickering signaled the end of Earth’s most recent cold spell, the so-called Younger Dryas period. The authors of the new review, led by Marten Scheffer of Wageningen University in The Netherlands, say that in a similar way, debilitating epileptic seizures can be preceded by frequent small symptomless seizures - the ‘flickers’ of the epileptic brain.

Continue reading "Why a climate crisis is like an epileptic seizure" »

Posted by Anna Barnett on September 03, 2009
Categories: Anna Barnett, Climate prediction, Earth science, Extreme Events | Permalink | Comments (1) | TrackBacks (0)

Jane Qiu has an interesting interview on Nature News with aquatic ecologist Breck Bowden of the University of Vermont, who is heading up new research looking at what happens when thawing ground in the Arctic begins to fall apart. Here's an excerpt:

Last week marked the start of a US$5 million project to study the effects of thawing permafrost on ecosystems in the Arctic. Based at the Toolik Field Station in northern Alaska and sponsored by the US National Science Foundation, the project will look at the impact of thermokarsts — the scars and pits left behind as melt water from permanently frozen ground leaks away, and soil and rock collapses in its wake.

The project was inspired by a serendipitous discovery in 2003, says Bowden:

My colleagues and I were flying over the high Arctic in search of research sites. We noted that the Toolik River was brown and muddy, which was odd as it hadn't rained recently. As we went further upstream, we came to a tiny stream that was washing tons of thermokarst sediments into the river. We were astounded how this tiny feature was influencing the river 40 kilometres downstream. The volume that had been displaced was enough to smother the bottom of the entire river. The sediments would release a lot of nutrients normally locked up in permafrost into freshwater cycles. That's got to have a significant impact on the ecosystem.

Read the full interview here.

Anna Barnett

Posted by Anna Barnett on July 01, 2009
Categories: Anna Barnett, Cryosphere, Earth science | Permalink | Comments (0) | TrackBacks (0)

China’s forests, shrublands and soils have absorbed a third or so of China’s fossil fuel emissions from 1980 to 2000. Sequestering up to 260 million tonnes of carbon per year, the Chinese land sink is more than twice as large than that of geographic Europe, and comparable in size to that of the United States.

There has been quite some controversy over the total size of the Northern Hemisphere’s terrestrial carbon sink, so this first comprehensive estimate, published in Nature today, is filling a real gap. Given China’s 1.2 billion population and rapidly growing economy, knowledge of how much of its emissions are actually staying in the atmosphere is pretty valuable information. Globally, around 40% of annual emissions stay in the atmosphere; the rest is sequestered by plants, soils and oceans.

The Chinese data come at a time of growing speculation and guesswork over the People's Republic’s future climate and energy policies. Needless to say, the study is of no small relevance with a view to upcoming climate negotiations. The very fact that China’s land carbon sink is large is good news. But the results will also strengthen the Chinese government’s negotiation position at the United Nations climate summit in December in Copenhagen.

Continue reading "EGU: China's carbon sink - it's large" »

Posted by Anna Barnett on April 22, 2009
Categories: Biosphere feedbacks, Climate Policy, Earth science, Mitigation, Politics, Quirin Schiermeier | Permalink | Comments (0) | TrackBacks (0)

What do Boston, London, New York, Frankfurt, San Francisco, and Paris have in common? They have all been destroyed by asteroid impacts—in the movies. The death toll was enormous in every case. Understandably, people are worried that such a catastrophe might actually occur within their lifetime.

Actually, says climate scientist Mark B. Boslough, “if you’re going to stay up late at night worrying about something, worry about climate.” Boslough, a researcher at the Sandia National Laboratories in Albuquerque, New Mexico, US, says, “you are much more likely to die from climate change than from an asteroid impact by a factor of something like a thousand.” He presented his findings at the Fall Meeting of the American Geophysical Union in San Francisco, California.

Boslough cannot put a precise number on that ratio, because climate science is still replete with gaps in the relevant data. He is much more confident about the asteroid threat, though. He says that there is no evidence that anyone has died from an asteroid or meteorite impact—ever. He does not make a distinction between asteroids and meteors, saying the latter are basically fragments of the former and there is no size boundary to distinguish one from the other.

Looking at worst case scenarios for asteroid impacts and climate change over the next 100 years, Boslough estimates that the largest asteroid to impact Earth would be around 50 metres in diameter. It would explode in the atmosphere and not make an impact crater, he says, and it would kill no one. Asteroids larger than 50 metres across and likely to cross Earth’s orbit are rare, and the larger they are, the rarer they are. They are also well tracked. Smaller ones are more numerous, but even less likely to cause death and destruction on Earth.

Continue reading "AGU 2008: Asteroid impacts and climate change: which is the greater threat?" »

Posted by Olive Heffernan on December 19, 2008
Categories: Recent contributors, AGU, Communicating Climate Change, Earth science, Harvey Leifert, Society | Permalink | Comments (1) | TrackBacks (0)

There’s a line around the block to give advice to Barack Obama, the latest offering being a 400-page environmental policy paper backed by 29 NGOs (hat tip to Climate Progress). Amid the many recommendations, a proposed bureaucratic shake-up of US Earth science has also resurfaced.

The idea is to combine research programs at NOAA and the USGS into a new, streamlined Earth Systems Science Agency, or ESSA. Published as a Policy Forum in Science this past July (subscription required; also see NRCC story and blog), it is now very much dwarfed by buzz about a possible National Energy Council complete with a czar to be crowned. But ESSA hasn’t fallen entirely off the radar of influential democrats - more on this below. And there’s just been an interesting dialogue over at Prometheus on whether the NOAA-USGS merger makes sense.

Continue reading "Attn Obama: Earth science agency merger" »

Posted by Anna Barnett on November 27, 2008
Categories: Anna Barnett, Earth science, In the News, Politics | Permalink | Comments (0) | TrackBacks (0)

Cross-posted from Daniel Cressey on The Great Beyond

Cyclones appear to be responsible for a large amount of organic carbon tied up in ocean sediments.

In a paper published in Nature Geoscience, Robert Hilton and colleagues report on the impact of cyclone-induced floods on carbon in the LiWu River in Taiwan. They found that between 77 and 92% of non-fossil carbon eroded from the LiWu catchment area was moved during floods linked to cyclones.

As increased sea surface temperatures from global warming could increase the intensity of cyclones, this could create negative feedback, with bigger cyclones locking up more organic carbon in sediments. Sadly this is not going to stop global warming.

Continue reading "Cyclones’ carbon capturing" »

Posted by Anna Barnett on October 20, 2008
Categories: Atmospheric Science, Climate Science, Daniel Cressey, Earth science, Hurricanes, Ocean science | Permalink | Comments (0) | TrackBacks (0)

It's a buried time bomb of greenhouse emissions - and it's even less photogenic than melting permafrost. A team of researchers led by Takeshi Ise of the Japan Agency for Marine-Earth Science and Technology has been watching peat dry.

Peat - "an accumulation of partially decayed vegetation matter", in Wikipedia's appetizing phrase - forms in bogs and swamps where the acidic, waterlogged, oxygen-poor soil smothers the decomposition process, just as permafrost freezes it out. That makes it a big sink for carbon that would otherwise have joined the atmosphere as the plants composted. But peat's not just a sink, it's a sump - and a snowballing one. The large amount of water peat can hold lowers the oxygen available, which makes more peat accumulate, which sucks up more groundwater and blocks it from draining.

It's this feedback process, as it occurs in the northern bogs of Manitoba, Canada, that Ise et al. succeeded in accurately modeling for the first time in a paper published this week in Nature Geoscience (subscription required). Their bad news is that warming air temperatures reverse the loop: the peat dries and decays, then can't hold as much water and dries and decays some more.

As Joseph Romm points out on Grist and Climate Progress, that potentially makes the peat loop a link in a bigger, and climatically more important, vicious circle - the one where temperatures raised by human emissions start an uncontrollable release of methane and carbon dioxide from natural stores like peat and permafrost.

Continue reading "Watching peat dry" »

Posted by Anna Barnett on October 16, 2008
Categories: Anna Barnett, Biosphere feedbacks, Climate Science, Earth science | Permalink | Comments (0) | TrackBacks (0)

The Great Plains of the United States, late twenty-first century: breadbasket or dust bowl?

It may depend on groundwater storage, finds a study published in Nature Geoscience this week (subscription required). The results are based on an unusually sophisticated watershed model that connects the below-ground water sources, surface water and the land surface itself.

Continue reading "Breadbasket or dust bowl?" »

Posted by Anna Barnett on September 30, 2008
Categories: Anna Barnett, Climate Science, Earth science, Regional climate | Permalink | Comments (3) | TrackBacks (0)

The next US president should merge two huge government research agencies to bring forth a new independent and comprehensive Earth science body - that’s the idea put forth in a commentary by former agency heads in Science yesterday (subscription required). They call for NOAA and the USGS become a single Earth Systems Science Agency, ESSA.

That merger would ring a few nostalgic bells, since NOAA was once also called ESSA (for Environmental Science Services Administration). And it would bureaucratically marry the atmospheric and ocean research at NOAA to the terrestrial, freshwater and biological studies at the USGS. To face the daunting agenda of “climate change, sea-level rise, altered weather patterns, declines in freshwater availability and quality, and loss of biodiversity,” the authors say, the US needs massive scientific support from an integrated, streamlined institution - one as seamless as the Earth system itself.

But would ESSA really produce better science? The proposal’s authors have tempting suggestions for changes under a new agency, not least upping the amount of money that would leave the building: grants to outside researchers total a few percent of current NOAA and USGS budgets, they told me, but they want the sum to be at least 25% at ESSA. They also call for Big Science modelling and monitoring programs, and even for research into breakthrough green tech, a la DARPA.

Such plans would have to be hashed out over and above the decision to put ESSA together, however. Meanwhile, trying to mesh the USGS and NOAA missions could have interesting effects. What would happen, for example, to NOAA's marine fisheries programs? NOAA is housed in the Department of Commerce, where commercial fishing interests are sometimes seen to clash with conservation. Mark Schaefer, former USGS director and the ESSA proposal’s lead author, said creating the hoped-for independent, nonregulatory agency might mean moving fisheries regulation to the Fish and Wildlife Service in the Department of the Interior, where protecting natural resources is key.

Continue reading "One earth, one US agency" »

Posted by Anna Barnett on July 04, 2008
Categories: Anna Barnett, Earth science, Politics | Permalink | Comments (1) | TrackBacks (0)