White House warned on imminent Arctic ice death spiral

National security officials worried by rapid loss of Arctic summer sea ice overlook threat of permanent global food shortages

The melting of sea ice in the Arctic has caught the eye of the US Department of Homeland Security and the Pentagon. Photograph: John McConnico/AP

Senior US government officials are to be briefed at the White House this week on the danger of an ice-free Arctic in the summer within two years.

The meeting is bringing together NASA's acting chief scientist, Gale Allen, the director of the US National Science Foundation, Cora Marett, as well as representatives from the US Department of Homeland Security and the Pentagon.

This is the latest indication that US officials are increasingly concerned about the international and domestic security implications of climate change.

Senior scientists advising the US government at the meeting include 10 Arctic specialists, including marine scientist Prof Carlos Duarte, director of the Oceans Institute at the University of Western Australia.

In early April, Duarte warned that the Arctic summer sea ice was melting at a rate faster than predicted by conventional climate models, and could be ice free as early as 2015 – rather than toward the end of the century, as the UN Intergovernmental Panel on Climate Change (IPCC) projected in 2007. He said:

"The Arctic situation is snowballing: dangerous changes in the Arctic derived from accumulated anthropogenic green house gases lead to more activities conducive to further greenhouse gas emissions. This situation has the momentum of a runaway train."

Duarte is lead author of a paper published last year in Nature Climate Change documenting how "tipping elements" in the Arctic ecosystems leading to "abrupt changes" that would dramatically impact "the global earth system" had "already started up." Duarte and his team concluded: "We are facing the first clear evidence of dangerous climate change."

New NASA satellite imagery from March 2013 reveals massive cracks in ice connecting Beaufort Gyre region to Alaska

New research suggests that the Arctic summer sea ice loss is linked to extreme weather. Rutgers University climate scientist Jennifer Francis points to the phenomenon of "Arctic amplification," where:

"The loss of Arctic summer sea ice and the rapid warming of the Far North are altering the jet stream over North America, Europe, and Russia. Scientists are now just beginning to understand how these profound shifts may be increasing the likelihood of more persistent and extreme weather."

Extreme weather events over the last few years apparently driven by the accelerating Arctic melt process – including unprecedented heatwaves and droughts in the US and Russia, along with snowstorms and cold weather in northern Europe – have undermined harvests, dramatically impacting global food production and contributing to civil unrest.

US national security officials have taken an increasing interest in the destabilising impact of climate change. In February this year, the US Department of Defense (DoD) released its new Climate Change Adaptation Roadmap, which noted that global warming will have:

"... significant geopolitical impacts around the world, contributing to greater competition for more limited and critical life-sustaining resources like food and water."

The effects of climate change may:

"Act as accelerants of instability or conflict in parts of the world... [and] may also lead to increased demands for defense support to civil authorities for humanitarian assistance or disaster response, both within the United States and overseas … DoD will need to adjust to the impacts of climate change on its facilities, infrastructure, training and testing activities, and military capabilities."

The primary goal of adaptation is to ensure that the US armed forces are "better prepared to effectively respond to climate change" as it happens, and "to ensure continued mission success" in military operations – rather than to prevent or mitigate climate change.

While the DoD is also concerned about the Arctic, the focus is less on risks than on opportunities:

"The Department is developing cooperative partnerships with interagency and international Arctic stakeholders to collaboratively address future opportunities and potential challenges inherent in the projected opening of the Arctic."

Arctic "stakeholders" include US, Russian, Canadian, Norwegian and Danish energy firms, which are scrambling to exploit the northern polar region's untapped natural wealth. The region is estimated to hold a quarter of the world's remaining undiscovered oil and gas reserves, sparking concerted efforts by these countries to expand their Arctic military presence.

The US Homeland Security Department's Climate Change Roadmapreleased last year raised similar issues, warning that climate change "could directly affect the Nation's critical infrastructure," as well as aggravating "conditions that could enable terrorist activity, violence, and mass migration."

On the Arctic, the report highlights the imperative to protect US resource interests by increasing regional military penetration:

"Melting sea ice in the Arctic may lead to new opportunities for shipping, tourism, and resource exploration, but the increase in human activity may require a significant increase in operational capabilities in the region in order to safeguard lawful trade and travel and to prevent exploitation of new routes for smuggling and trafficking."

A public statement in response to news of the White House's Arctic briefing released on Tuesday by the UK-based Arctic Methane Emergency Group (AMEG) – a group of international climate scientists – called on governments to recognise that the dramatic loss of summer sea ice in the Arctic would amplify the types of extreme weather events that have already affected the world's major food basket regions, undermining global food production for the foreseeable future with serious consequences for international security.

The group, which includes among its founding members leading Arctic specialists such as Prof Peter Wadhams, head of the Polar Ocean Physics Group at Cambridge University, stated that:

"The weather extremes from last year are causing real problems for farmers, not only in the UK, but in the US and many grain-producing countries. World food production can be expected to decline, with mass starvation inevitable. The price of food will rise inexorably, producing global unrest and making food security even more of an issue."

The AMEG statement adds that governments should consider geoengineering techniques – large-scale technological interventions in the climate system – to "cool the Arctic and save the sea ice" in order to avert catastrophe. Critics point out, however, that untested geoengineering technologies could have damaging unintended impacts on ecosystems, and that a regulatory framework is needed before embarking on major projects.

Dr Nafeez Ahmed is director of the Institute for Policy Research & Development and author of A User's Guide to the Crisis of Civilisation: And How to Save It.

http://www.guardian.co.uk/environment/earth-insight/2013/may/02/white-house-arctic-ice-death-spiral

Andrew Glikson: No alternative to atmospheric CO2 draw-down

by Andrew Glikson, Skeptical Science, February 14, 2013

This article suggests that the current atmospheric CO₂ level is already triggering amplifying feedbacks from the Earth system and therefore, in themselves, efforts at reduction in atmospheric CO₂-emission are no longer sufficient to prevent further global warming. For this reason, along with sharp reductions in carbon emissions, efforts need to be undertaken in an attempt to reduce atmospheric CO₂ levels from their current level of nearly 400 ppm to well below 350 ppm. NASA-applied, outer space–shade technology may buy time for such a planetary defence effort.

The scale and rate of modern climate change have been greatly underestimated. The release to date of a total of over 560 billion ton of carbon through emissions from industrial and transport sources, land clearing and fires, has raised CO₂ levels from about 280 parts per million (ppm) in pre-industrial periods to 397–400 ppm and near 470 ppm CO₂-equivalent (a value which includes the CO₂-equivalent effect of methane), reaching a current CO₂ growth rate of about 2 ppm per year.

Figure 1. Part A. Mean CO₂ level from ice cores, Mouna Loa observatory and marine sites; Part B (inset). Climate forcing 1880–2003. Aerosol forcing includes all aerosol effects, including indirect effects on clouds and snow albedo. GHGs include ozone (O₃) and stratospheric H₂O, in addition to well-mixed greenhouse gases.

Figure 2: Relations between CO₂ rise rates and mean global temperature rise rates during warming periods, including the Paleocene–Eocene Thermal Maximum, Oligocene, Miocene, glacial terminations, Dansgaard–Oeschger cycles and the post-1750 period.

These developments are shifting the Earth’s climate toward Pliocene-like (5.2–2.6 million years ago; mean global temperatures of +2–3 ^oC above pre-industrial temperatures) and possibly toward mid-Miocene-like (approximately 16 million years ago; mean global temperatures +4 ^oC above pre-industrial temperatures) conditions within a few centuries ― a geological blink of an eye.

The current CO₂ level generates amplifying feedbacks, including the reduced capacity of warming water to absorb CO₂ from the atmosphere, CO₂ released from fires, droughts, loss of vegetation cover, disintegration of methane released from bogs, permafrost and methane-bearing ice particles and methane-water molecules.

With CO₂ atmospheric residence times in the order of thousands to tens of thousands years, protracted reduction in emissions, either flowing from human decision or due to reduced economic activity in an environmentally stressed world, may no longer be sufficient to arrest the feedbacks.

Four of the large mass extinction of species events in the history of Earth (end-Devonian, Permian–Triassic, end-Triassic, K–T boundary) have been associated with rapid perturbations of the carbon, oxygen and sulphur cycles, on which the biosphere depends, at rates to which species could not adapt.

Since the 18th century, and in particular since about 1975, the Earth system has been shifting away from Holocene (approximately 10,000 years to the pre-industrial time) conditions, which allowed agriculture, previously hindered by instabilities in the climate and by extreme weather events. The shift is most clearly manifested by the loss of polar ice. Sea level rises have been accelerating, with a total of more than 20 cm since 1880 and about 6 cm since 1990.

For a temperature rise of 2.3 ^oC, to which the climate is committed if sulphur aerosol emission discontinues (see Figure 1), sea levels would reach Pliocene-like levels of 25 meters plus or minus 12 meters, with lag effects due to ice sheet hysteresis (system inertia).

With global atmospheric CO₂-equivalents (a value which includes the effect of methane) above 470 ppm (just under the upper stability limit of the Antarctic ice sheet, with the current rate of CO₂ emissions from fossil fuel combustion, cement production, land clearing and fires of ~9.7 billion ton of carbon in 2010), global civilization faces the following alternatives:

1. With carbon reserves sufficient to raise atmospheric CO₂ levels to above 1,000 ppm, continuing business-as-usual emissions can only result in advanced melting of the polar ice sheets, a corresponding rise of sea levels on the scale of meters to tens of meters, on a time scale of decades to centuries, and high-to-extreme continental temperatures rendering agriculture and human habitat over large regions unlikely.
2. With atmospheric CO₂ at about 400 ppm, an abrupt decrease in carbon emissions may no longer be sufficient to prevent current feedbacks (melting of ice, methane release from permafrost, fires). Attempts to stabilize the climate require global efforts at CO₂ draw-down, using a range of methods, including global reforestation, extensive biochar application, chemical CO₂ sequestration (using sodium hydroxide, serpentine and new innovations), as well as burial of CO₂.

As indicated in Table 1, the use of short-term solar radiation shields such as sulphur aerosols cannot be regarded as more than a band aid, with severe deleterious consequences in terms of ocean acidification and retardation of the monsoon and of precipitation over large parts of the Earth.

In contrast, retardation of solar radiation through space sunshade technology may allow time for CO₂ draw-down. Unlike sulphur dioxide injections, this will not have ocean acidification effects – an effort requiring a planetary defense project by NASA.

Dissemination of ocean iron filings aimed at increasing fertilization by plankton and algal blooms, or temperature exchange through vertical ocean pipe systems, are unlikely to constitute effective means of transporting CO₂ to relatively safe water depths.

In contrast to these methods, CO₂ sequestration through fast-track reforestation, soil carbon, biochar and possible chemical methods such as “sodium trees” and serpentine (combining Ca and Mg with CO2) may be effective, provided these are applied on a global scale.

Such efforts will require an effective planetary defense effort on the scale currently expended on military spending (totaling more than $20 trillion since WWII).

It is likely that a species which decoded the basic laws of nature, split the atom, placed a man on the moon and ventured into outer space should also be able to develop the methodology for fast sequestration of atmospheric CO₂. The alternative, in terms of global heating, sea level rise, extreme weather events, and the destruction of the world’s food sources is unthinkable.

Good planets are hard to come by.

http://www.skepticalscience.com/No-alternative-atmospheric-CO2-draw-down.html

"Management of trade-offs in geoengineering through optimal choice of non-uniform radiative forcing," by Douglas G. MacMartin, David W. Keith, Ben Kravitz & Ken Caldeira, Nature Climate Change, doi:10.1038/nclimate1722

Nature Climate Change, 2(10) (October 2012); doi:10.1038/nclimate1722

Management of trade-offs in geoengineering through optimal choice of non-uniform radiative forcing

Douglas G. MacMartin, David W. Keith, Ben Kravitz and Ken Caldeira

Abstract

Solar radiation management could be used to offset some or all anthropogenic radiative forcing, with the goal of reducing some of the associated climatic change^{1, 2}. However, the degree of compensation will vary, with residual climate changes larger in some regions than others. Similarly, the insolation reduction that best compensates climate changes in one region may not be the same as for another, leading to concerns about equity³. Here we show that optimizing the latitudinal and seasonal distribution of solar reduction can improve the fidelity with which solar radiation management offsets anthropogenic climate change. Using the HadCM3L general circulation model, we explore several trade-offs. First, residual temperature and precipitation changes in the worst-off region can be reduced by 30% relative to uniform solar reduction, with only a modest impact on global root-mean-square changes; this has implications for moderating regional inequalities. Second, the same root-mean-square residual climate changes can be obtained with up to 30% less insolation reduction, implying that it may be possible to reduce solar radiation management side-effects and risks (for example, ozone depletion if stratospheric sulphate aerosols are used). Finally, allowing spatial and temporal variability increases the range of trade-offs to be considered, raising the question of how to weight different objectives.

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1722.html

Call for Arctic geoengineering as soon as possible -- see comment by John Nissen

Call for Arctic geoengineering as soon as possible

by Peter Aldhous, NewScientist, December 12, 2011

It's the most urgent call for geoengineering yet: begin cooling the Arctic by 2013 or face runaway global warming. But the warning – from a voice on the scientific fringe – may be premature, according to experts contacted by New Scientist.

John Nissen, a former software engineer who has become alarmed at the possibility of reaching a climate "tipping point" argued for Arctic geoengineering as soon as possible in a poster presentation at the American Geophysical Union meeting in San Francisco last week.

"We've got to pull out all the stops to prevent a runaway situation," Nissen says. He suggests using stratospheric aerosols to cool the surface and subsurface below, or increasing the reflectance of low-level clouds by pumping a fine spray of salt water into them.

Although Nissen's opinion is not in the scientific mainstream, he has the backing of a leading expert on sea ice, Peter Wadhams of the University of Cambridge, who recently suggested that the Arctic ocean may be ice-free at the end of each summer from 2015 onwards. Wadhams says that accelerating climate change in the Arctic has forced him to abandon his scepticism about geoengineering. "One has to consider doing something," he says.

Gas leak

As the Arctic loses its shield of ice in the summer months, shallow waters over the east Siberian Arctic continental shelf will warm to several degrees above freezing. This is the largest continental shelf on the planet, covering 2.1 million square kilometres, and the sea above it is just 50 metres deep on average. The seabed consists largely of methane-rich permafrost, which began to be submerged about 8,000 years ago, as the sea level rose following the last ice age. Without a protective cap of sea ice over the shallow water, the permafrost will warm rapidly and release huge amounts of methane, Nissen fears.

Nissen's alarm about catastrophic methane release stems in part from the findings of a team led by Natalia Shakhova of the International Arctic Research Center at the University of Alaska Fairbanks. Last year she reported large amounts of methane bubbling from the east Siberian Arctic shelf.

Ice-free when?

However, both the sea-ice projections and the fears about catastrophic methane releases are shrouded in uncertainty. Wieslaw Maslowski of the Naval Postgraduate School in Monterey, California, has developed a regional model that suggests an ice-free Arctic Ocean by the end of the summer from 2016 onwards. But global climate models suggest that this won't happen until 2030 at the earliest.

One contributor to the Arctic Sea Ice Blog, meanwhile, has fitted exponential curves to data on ice volume and projected forward to get a date of 2015 for the complete loss of late-summer sea ice. The problem is that other curves fit the data similarly well, but give much later dates when extrapolated forward. "If you pick one curve over another, I'd like to see a good reason for doing so," says Axel Schweiger of the University of Washington in Seattle.

Uncertainty analysis

It's also unclear how much methane, in total, is bubbling from the east Siberian Arctic shelf – and whether the methane release observed by Shakhova and her colleagues is due to present warming or is the result of the permafrost slowly melting since it was inundated beginning eight millennia ago. "There are still more questions than answers," says Igor Semiletov, a member of the team.

What's more, says Euan Nisbet of Royal Holloway, University of London, it seems that the largest current releases of methane are coming from the southern hemisphere tropics, rather than the Arctic.

Given the uncertainties, Nissen's proposal seems unlikely to take off. However, it heightens the need for governments to develop guidelines for future geoengineering that may become necessary. "There is very much an urgent need to addresses governance issues," says Tim Kruger of the University of Oxford, part of a team that has developed a "code of conduct" for geoengineering research.

http://www.newscientist.com/article/dn21275-call-for-arctic-geoengineering-as-soon-as-possible.html

Why Geoengineering So Soon

Tue Dec 13 02:41:22 GMT 2011 by John Nissen

Dear Peter Aldhous,

I need to explain the simple chain of reasoning behind the call for geoengineering by 2013, and why it is ridiculous to suggest that it is premature when, if anything, it may be too late.

As Peter Wadhams agrees, geoengineering to cool the Arctic is the only possible way to halt the sea ice retreat. Even with geoengineering it may prove impossible, but the later we leave it, the less likely we are to succeed. Once the Arctic Ocean has been practically sea ice free at the end of summer, all the ice formed over the following winter will be young ice and easily melted the following spring and summer. Therefore we have to try our hardest not to get to this point, because it could be the point of no return to a cooler Arctic. Past this point and the Arctic will be warming faster than ever from the absorption of sunlight in the open water where the ice had been. This warming is liable to thaw sub-sea permafrost holding back vast stores of methane in the continental shelf regions that Natalia Shakhova and Igor Semiletov have studied. Methane is already seen to be bubbling out from the seabed.

Now methane is a potent greenhouse gas. Release of only a small percentage of this sub-sea methane could cause sufficient warming to trigger further methane release and further warming in a runaway process, akin to what is thought to have happened in the PETM extinction event, 55 million years ago, when the global temperature rose many degrees. We simply have to do all we can to prevent such a process getting underway as it would be unstoppable. So first we have to halt the sea ice retreat.

Considering simple logistics, the earliest conceivable time to start applying geoengineering cooling technologies would be spring 2013, which is why I am urging governments to back an emergency action plan for geoengineering with that target date.

To me it seems common sense to do our utmost to prevent reaching a point of no return – a point beyond which runaway global warming could be inevitable.

J. C. Moore, S. Jevrejeva & A. Grinsted, PNAS (2010), Efficacy of geoengineering to limit 21st century sea-level rise

Proceedings of the National Academy of Sciences, published online before print August 23, 2010; doi: 10.1073/pnas.1008153107

Efficacy of geoengineering to limit 21st century sea-level rise

J. C. Moore*, S. Jevrejeva and A. Grinsted

Abstract

Geoengineering has been proposed as a feasible way of mitigating anthropogenic climate change, especially increasing global temperatures in the 21st century. The two main geoengineering options are limiting incoming solar radiation, or modifying the carbon cycle. Here we examine the impact of five geoengineering approaches on sea level; SO₂ aerosol injection into the stratosphere, mirrors in space, afforestation, biochar, and bioenergy with carbon sequestration. Sea level responds mainly at centennial time scales to temperature change, and has been largely driven by anthropogenic forcing since 1850. Making use a model of sea-level rise as a function of time-varying climate forcing factors (solar radiation, volcanism, and greenhouse gas emissions) we find that sea-level rise by 2100 will likely be 30 cm higher than 2000 levels despite all but the most aggressive geoengineering under all except the most stringent greenhouse gas emissions scenarios. The least risky and most desirable way of limiting sea-level rise is bioenergy with carbon sequestration. However aerosol injection or a space mirror system reducing insolation at an accelerating rate of 1 W m^-2 per decade from now to 2100 could limit or reduce sea levels. Aerosol injection delivering a constant 4 W m^-2

reduction in radiative forcing (similar to a 1991 Pinatubo eruption every 18 months) could delay sea-level rise by 40–80 years. Aerosol injection appears to fail cost-benefit analysis unless it can be maintained continuously, and damage caused by the climate response to the aerosols is less than about 0.6% Global World Product. 

*Correspondence e-mail: john.moore.bnu@gmail.com.
 
Link:  http://www.pnas.org/content/early/2010/08/20/1008153107

J. C. Moore, S. Jevrejeva & A. Grinsted: Geoengineering 'not a solution' to sea-level rise

Geoengineering 'not a solution' to sea-level rise

by Katia Moskvitch Science reporter, BBC News, August 24, 2010
 

 

There are many different approaches to geoengineering

Even the most extreme geoengineering approaches will not stop sea levels from rising due to climate change, a study suggests.

New research proposes that as many as 150 million people could be affected as ocean levels increases by 30-70 cm by the end of this century.

This could result in flooding of low-lying coastal areas, including some of the world's largest cities.

The team published the study in the journal PNAS.

Scientists led by John Moore from Beijing Normal University, China, write that to combat global warming, people need to concentrate on sharply curbing greenhouse gas emissions and not rely too much on proposed geoengineering methods.

"Substituting geoengineering for greenhouse emission control would be to burden future generations with enormous risk," said Svetlana Jevrejeva of the UK's National Oceanography Centre, a co-author of the study.

Geoengineering has been talked about for countering some of the effects of climate change for the past several years, with some figures like the billionaire Bill Gates ploughing millions of dollars into the research.

But Dr Jevrejeva told BBC News that some proposals such as placing mirrors in space and spraying aerosols -- microscopic particles -- into the sky would only treat the symptoms, as greenhouse gases would remain in the Earth's atmosphere.

Dr Jevrejeva and her colleagues examined two geoengineering schemes with five different scenarios.
 
'Not a solution'

The first approach involves limiting incoming solar radiation through the injection of SO2 (sulphur dioxide) aerosols into the stratosphere. Alternatively, giant mirrors could be launched into orbit, they said.

The second approach would involve modifying the carbon cycle by either planting more trees (afforestation), converting organic material into charcoal (biochar) or using renewable energy from materials derived from biological sources (bioenergy).

"We used [a computer model to track] 300 years of tide gauge measurements to reconstruct how sea level responded historically to changes in the amount of heat reaching the Earth from the Sun, the cooling effects of volcanic eruptions, and past human activities," said Dr Jevrejeva.

"We then used this information to simulate sea level under geoengineering schemes over the next 100 years," she added.

The team found that, if taken individually, even the most extreme of these methods would result in severe sea-level rise.

 

Placing a mirror into space could reflect some of the sunlight

"We suggested that the most effective approach would be a combination of three different techniques for managing the carbon cycle," said Dr Jevrejeva.

She explained that these scenarios relied on biological mechanisms to remove CO2 from the air and store it in biomass, soils or geological storage sites.

For instance, afforestation, or adding forests to places where they have been cut down or never existed, would lower the amount of atmospheric CO2, but only by 45 ppm (parts per million) -- a lot less than the amount humans have already emitted.

Biochar would reduce the CO2 levels by even less -- 35 ppm.


Biofuel production would be more effective, and the combination of the three methods could eliminate up to 250 ppm of CO2 and limit sea level rise to between 20 and 40 cm.
 
Carbon storage
 
The carbon storage technique also has other advantages, pointed out Dr Jevrejeva. It actually reduces the amount of CO2 in the atmosphere, whereas the method of reflecting sunlight back into space does not.

"If you use a mirror, it's extremely expensive and it's an engineering challenge -- you have to place mirrors [weighing] some 20 million tonnes into the Earth's orbit," Dr Jevrejeva explained.

There was also the chance these mirrors might break in orbit, the researcher added.

The same goes for SO2 aerosol injection -- a controversial approach that has already been tested on a small scale in Russia by one of the country's leading climatologists Yuri Israel.

"What worries me is that it's cheap and do-able and all you need is a country with a rocket”  Sir David King Former UK Chief Scientific Adviser

But Dr Jevrejeva said that even though injecting a certain amount of SO2 into the atmosphere might lower mean global temperatures by 1 °C or more over a few decades, the CO2 would still persist there. 

The researchers' simulations showed that spraying the stratosphere with aerosols would produce a similar effect to a major volcanic eruption occuring every 1.5 years. Besides reducing global temperatures, this approach would also delay sea-level rise by 40 to 80 years.

"During a natural volcanic eruption, there's usually a cooling effect in the atmosphere and a drop in sea level. We [followed] different scenarios using the amount of aerosols equivalent to the biggest eruption of the 20th Century -- the eruption of Mount Pinatubo in 1991," said Dr Jevrejeva.

"Particles from volcanic ashes end up in the stratosphere and reflect the radiation from the sun, but the same amount of CO2 stays in the atmosphere, so you do not solve the problem."

Also, no one knows the effect such spraying could have on the ecosystem, added the scientist.

"It's a huge challenge, no one knows what could happen."

In the Proceedings of the National Academy of Sciences (PNAS), the scientists wrote that SO2 injection into the atmosphere would likely lead to such undesirable consequences as "disruption in precipitation patterns and stratospheric ozone, and do nothing to avert the continued absorption of CO2 by the global ocean leading to rising acidity and ecosystem damage."

This controversial technique has already been tested in Russia, where scientists led by climatologist Professor Israel sprayed aerosols into the atmosphere from a small aircraft.
 
Major concerns

Professor Israel told BBC News that a stratospheric layer of SO2 could effectively cool the planet and would be an effective and none-too-expensive way of tackling climate change.

But there are also many opponents of geoengineering techniques, among them former UK chief scientific adviser Sir David King.

He told BBC News about his concerns over geoengineering proposals, especially those involving spraying the stratosphere with aerosols.

"What worries me is that it's cheap and do-able and all you need is a country with a rocket and they can put aerosols up into the stratosphere. We have no confidence in models on what these aerosols would do there.

Sir David explained: "Imagine if the aerosols would in some way cause more aerosol production -- because there are a lot of chemicals there including ozone -- and in time we find that we're getting more than we anticipated so the planet gets cooler and cooler when we wanted it to be stable."

Link:  http://www.bbc.co.uk/news/science-environment-11076786

Charles G. Trick et al., PNAS, 2010, Iron enrichment stimulates toxic diatom production in high-nitrate, low-chlorophyll areas

Proceedings of the National Academy of Sciences, published online before print March 15, 2010; doi: 10.1073/pnas.0910579107

Iron enrichment stimulates toxic diatom production in high-nitrate, low-chlorophyll areas

Charles G. Trick* (Departments of Biology, and Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A5B7, Canada), Brian D. Bill (Romberg Tiburon Center for Environmental Studies, San Francisco State University, Tiburon, CA 94920, and Marine Biotoxin Program, National Oceanic and Atmospheric Administration, Northwest Fisheries Science Center, Seattle, WA 98112, U.S.A.), William P. Cochlan (Romberg Tiburon Center for Environmental Studies, San Francisco State University, Tiburon, CA 94920, U.S.A.), Mark L. Wells (School of Marine Science, University of Maine, Orono, ME 04469, U.S.A.), Vera L. Trainer (Marine Biotoxin Program, National Oceanic and Atmospheric Administration, Northwest Fisheries Science Center, Seattle, WA 98112, U.S.A.) and Lisa D. Pickell (School of Marine Science, University of Maine, Orono, ME 04469, U.S.A.)

Edited by Penny W. Chisholm, Massachusetts Institute of Technology, Cambridge, MA, and approved February 1, 2010 (received for review September 23, 2009)

Abstract

Oceanic high-nitrate, low-chlorophyll environments have been highlighted for potential large-scale iron fertilizations to help mitigate global climate change. Controversy surrounds these initiatives, both in the degree of carbon removal and magnitude of ecosystem impacts. Previous open ocean enrichment experiments have shown that iron additions stimulate growth of the toxigenic diatom genus Pseudonitzschia. Most Pseudonitzschia species in coastal waters produce the neurotoxin domoic acid (DA), with their blooms causing detrimental marine ecosystem impacts, but oceanic Pseudonitzschia species are considered nontoxic. Here we demonstrate that the sparse oceanic Pseudonitzschia community at the high-nitrate, low-chlorophyll Ocean Station PAPA (50° N, 145° W) produces approximately 200 pg DA L⁻¹ in response to iron addition, that DA alters phytoplankton community structure to benefit Pseudonitzschia, and that oceanic cell isolates are toxic. Given the negative effects of DA in coastal food webs, these findings raise serious concern over the net benefit and sustainability of large-scale iron fertilizations. 

*Ccorrespondence e-mail: trick@uwo.ca.

Link to abstract:  http://www.pnas.org/content/early/2010/02/24/0910579107.abstract

Link to complete, open-access paper:  http://www.pnas.org/content/early/2010/02/24/0910579107.full.pdf+html

Gabriele C. Hegerl & Susan Solomon, Science, Vol. 325 (2009), Risks of climate engineering

Originally published in Science Express on 6 August 2009. Science (21 August 2009) Vol. 325, No. 5943, pp. 955-956; DOI: 10.1126/science.1178530

Perspectives

Climate Change: Risks of Climate Engineering

Gabriele C. Hegerl¹ and Susan Solomon²

As the risks of climate change and the difficulty of effectively reducing greenhouse gas emissions become increasingly obvious, potential geoengineering solutions are widely discussed. For example, in a recent report, Blackstock et al. explore the feasibility, potential impact, and dangers of shortwave climate engineering, which aims to reduce the incoming solar radiation and thereby reduce climate warming (1). Proposed geoengineering solutions tend to be controversial among climate scientists and attract considerable media attention (2, 3). However, by focusing on limiting warming, the debate creates a false sense of certainty and downplays the impacts of geoengineering solutions.

¹ Grant Institute, Kings Buildings, West Mains Road, Edinburgh EH9 3JW, U.K.
² National Oceanic and Atmospheric Administration, Earth System Research Laboratory, 325 Broadway R/CSD, Boulder, CO 80305–3337, U.S.A.

e-mail: gabi.hegerl@ed.ac.uk; susan.solomon@noaa.gov

Real Climate: A biased economic analysis of geoengineering

Real Climate: A biased economic analysis of geoengineering

Real Climate, group, 11 August 2009

Guest commentary by Alan Robock – Rutgers University

Bjorn Lomborg’s Climate Consensus Center just released an un-refereed report on geoengineering, An Analysis of Climate Engineering as a Response to Global Warming, by J Eric Bickel and Lee Lane. The “consensus” in the title of Lomborg’s center is based on a meeting of 50 economists last year. The problem with allowing economists to decide the proper response of society to global warming is that they base their analysis only on their own quantifications of the costs and benefits of different strategies. In this report, discussed below, they simply omit the costs of many of the potential negative aspects of producing a stratospheric cloud to block out sunlight or cloud brightening, and come to the conclusion that these strategies have a 25-5000 to 1 benefit/cost ratio. That the second author works for the American Enterprise Institute, a lobbying group that has been a leading global warming denier, is not surprising, except that now they are in favor of a solution to a problem they have claimed for years does not exist.

Geoengineering has come a long way since first discussed here three years ago. [Here I use the term “geoengineering” to refer to “solar radiation management” (SRM) and not to carbon capture and sequestration (called “air capture” in the report), a related topic with quite different issues.] In a New Scientist interview, John Holdren, President Obama’s science adviser, says geoengineering has to be examined as a possible response to global warming, but that we can make no such determination now. A two-day conference on geoengineering organized by the U.S. National Academy of Sciences was held in June, 2009, with an opening talk by the President, Ralph Cicerone. The American Meteorological Society (AMS) has just issued a policy statement on geoengineering, which urges cautious consideration, more research, and appropriate restrictions. But all this attention comes with the message that we know little about the efficacy, costs, and problems associated with geoengineering suggestions, and that much more study is needed.

Bickel and Lane, however, do not hesitate to write a report that is rather biased in favor of geoengineering using SRM, by emphasizing the low cost and dismissing the many possible negative aspects. They use calculations with the Dynamic Integrated model of Climate and the Economy (DICE) economic model to make the paper seem scientific, but there are many inherent assumptions, and they up-front refuse to present their results in terms of ranges or error bars. Specific numbers in their conclusions make the results seem much more certain than they are. While they give lip service to possible negative consequences of geoengineering, they refuse to quantify them. Indeed, the purpose of new research is to do just that, but the tone of this report is to claim that cooling the planet will have overall benefits, which CAN be quantified. The conclusions and summary of the report imply much more certainty as to the net benefits of SRM than is really the case.

My main areas of agreement with this report are that global warming is an important, serious problem, that SRM with stratospheric aerosols or cloud brightening would not be expensive, and that we indeed need more research into geoengineering. The authors provide a balanced introduction to the issues of global warming and the possible types of geoengineering.

But Bickel and Lane ignore the effects of ocean acidification from continued CO2 emissions, dismissing this as a lost cause. Even without global warming, reducing CO2 emissions is needed to do the best we can to save the ocean. The costs of this continuing damage to the planet, which geoengineering will do nothing to address, are ignored in the analysis in this report. And without mitigation, SRM would need to be continued for hundreds of years. If it were stopped, by the loss of interest or means by society, the resulting rapid warming would be much more dangerous than the gradual warming we are now experiencing.

Bickel and Lane do not even mention several potential negative effects of SRM, including getting rid of blue skies, huge reductions in solar power from systems using direct solar radiation, or ruining terrestrial optical astronomy. They imply that SRM technologies will work perfectly, and ignore unknown unknowns. Not one cloud has ever been artificially brightened by injection of sea salt aerosols, yet this report claims to be able to quantify the benefits and the costs to society of cloud brightening.

They also imply that stratospheric geoengineering can be tested at a small scale, but this is not true. Small injections of SO2 into the stratosphere would actually produce small radiative forcing, and we would not be able to separate the effects from weather noise. The small volcanic eruptions of the past year (1.5 Tg SO2 from Kasatochi in 2008 and 1 Tg SO2 from Sarychev in 2009, as compared to 7 Tg SO2 from El Chichón in 1982 and 20 Tg SO2 from Pinatubo in 1991) have produced stratospheric clouds that can be well-observed, but we cannot detect any climate impacts. Only a large-scale stratospheric injection could produce measurable impacts. This means that the path they propose would lead directly to geoengineering, even just to test it, and then it would be much harder to stop, what with commercial interests in continuing (e.g., Star Wars, which has not even ever worked).

Bickel and Lane also ignore several seminal papers on geoengineering that present much more advanced scientific results than the older papers they cite. In particular, they ignore Tilmes et al. (2008), Robock et al. (2008), Rasch et al. (2008), and Jones et al. (2009).

With respect to ozone, they dismiss concerns about ozone depletion and enhanced UV by citing Wigley (2006) and Crutzen (2006), but ignore the results of Tilmes et al. (2008), who showed that the effects would prolong the ozone hole for decades and that deployment of stratospheric aerosols in a couple decades would not be safe as claimed here. Bickel and Lane assert, completely incorrectly, “On its face, though, it does not appear that the ozone issue would be likely to invalidate the concept of stratospheric aerosols.”

With respect to an Arctic-only scheme, they suggest in several places that it would be possible to control Arctic climate based on the results of Caldeira and Wood (2008) who artificially reduce sunlight in a polar cap in their model (the “yarmulke method”), whereas Robock et al. (2008) showed with a more realistic model that explicitly treats the distribution and transport of stratospheric aerosols, that the aerosols could not be confined to just the Arctic, and such a deployment strategy would affect the summer Asian monsoon, reducing precipitation over China and India. And Robock et al. (2008) give examples from past volcanic eruptions that illustrate this effect, such as the pattern of precipitation reduction after the 1991 Pinatubo eruption (Trenberth and Dai, 2007):

With respect to cloud brightening, Bickel and Lane ignore the Jones et al. (2009) results that cloud brightening would mainly cool the oceans and not affect land temperature much, so that it is an imperfect method at best to counter global warming. Furthermore Jones et al. (2009) found that cloud brightening over the South Atlantic would produce severe drought over the Amazon, destroying the tropical forest.

They also ignore a huge class of ethical and world governance issues. Whose hand would be on the global thermostat? Who would trust military aircraft or a multi-national geoengineering company to have the interests of the people of the planet foremost?

They do not seem to realize that volcanic eruptions affect climate change because of sulfate aerosols produced from sulfur dioxide gas injections into the stratosphere, the same that is proposed for SRM, and not by larger ash particles that fall out quickly after and eruption and do not cause climate change.

They dismiss air capture (“air capture technologies do not appear as promising as solar radiation management from a technical or a cost perspective”) but ignore the important point that it would have few of the potential side effects of SRM. Air capture would just remove the cause of global warming in the first place, and the only side effects would be in the locations where the CO2 would be sequestered.

For some reason, they insist on using the wrong units for energy flux (W) instead of the correct units of W/m^2, and then mix them in the paper. I cannot understand why they choose to make it so confusing.

The potential negative consequences of stratospheric SRM were clearly laid out by Robock (2008) and updated by Robock et al. (2009), which still lists 17 reasons why geoengineering may be a bad idea. One of those important possible consequences, the threat to the water supply for agriculture and other human uses, has been emphasized in a recent Science article by Gabi Hegerl and Susan Solomon.

Robock et al. (2009) also lists some benefits from SRM, including increased plant productivity and an enhanced CO2 sink from vegetation that grows more when subject to diffuse radiation, as has been observed after every recent large volcanic eruption. But the quantification of these and other geoengineering benefits, as well as the negative aspects, awaits more research.

It may be that the benefits of geoengineering will outweigh the negative aspects, and that most of the problems can be dealt with, but the paper from Lomborg’s center ignores the real consensus among all responsible geoengineering researchers. The real consensus, as expressed at the National Academy conference and in the AMS statement, is that mitigation needs to be our first and overwhelming response to global warming, and that whether geoengineering can even be considered as an emergency measure in the future should climate change become too dangerous is not now known. Policymakers will only be able to make such decisions after they see results from an intensive research program. Lomborg’s report should have stopped at the need for a research program, and not issued its flawed and premature conclusions.

Link: http://www.realclimate.org/index.php/archives/2009/08/a-biased-economic-analysis-of-geoengineering/