No quick fix for climate with geoengineering

It sounds like something from a sci-fi movie, but the artificial manipulation of the Earth’s climate has been touted as a possible strategy to reduce the effects of unmitigated climate change. Thanks to the painfully slow progress that has been made towards reducing our carbon emissions, there has been some surprisingly serious discussion about the prospect of geoengineering the climate in order to suit the needs of humans.

Of the various forms that have been suggested (large machines to suck CO2 from the air, space-borne mirrors to reflect sunlight, iron filings in the ocean), the mostly widely discussed option is the injection of vast quantities of sulphur into the stratosphere. In theory, the airborne particles would have the effect of reflecting solar radiation, and thereby the reducing warming effects of climate change.

Of course, this would do nothing to actually reduce carbon pollution (which would continue to increase with human development), not least anything to reduce the effects of ocean acidification and a myriad of other impacts upon biodiversity, ecosystems and human health. Geoengineering is certainly a drastic option fraught with uncertainty, but advocates of the approach have been considering back-up plans for the worst possible case scenario, while others have been looking into what effects may come if geoengineering became a reality.

A new study published in Nature Geoscience[1] last week has examined the possible consequences of large scale geoengineering on the planet from the baseline year of 2005. The authors simulated a range of geoengineering scenarios by making use of thousands of home computers that were volunteered as part of a large scale climate forecasting experiment.

They found that although the injection of trogospheric sulphur aerosols did in fact reduce global average temperatures compared to the unmitigated climate change scenario, global net precipitation would decrease as a result. The disparity between temperature and precipitation anomalies became increasingly apparent the longer that geoengineering activities were maintained in the modelled scenarios – meaning that over time it would become more and more difficult to regulate temperature and precipitation within “20th century climate conditions” simultaneously.

On top of these effects, the results also indicate that the degree of climate engineering undertaken (i.e the amount of aerosols pumped into the air) would impact upon different parts of the world in different ways. This regional variation in the effects of geo-engineering would make it even more difficult to choose an “optimum” level of climate manipulation – for example, keeping China close to its baseline climate meant undesirable conditions for India, and vice versa.

Although some of these results may be model-specific (such as the specific regional effects), this new study gives a frightening glimpse into the risks and uncertainties of climate geoengineering. The fact that we’re even considering the idea of large scale climate manipulation seems to be  indicative of society’s desire to seek technological fixes to treat the symptoms of a problem, instead of addressing the root cause. Clive Hamilton[2] describes the penchant of wealthy Texans to enjoy a log fire despite living in a hot climate, and so likens geoengineering to “responding to overheating by turning up the air-conditioning while continuing to pile more logs onto the file”.

But with the stifling of action on climate change both at home and abroad, is geoengineering a reality we are rapidly moving towards?

[1] Ricke, K. L., Morgan, M. G. & Allen, M. R. Nature Geosci. Advance online publication doi:10.1038/ngeo915

[2] Clive Hamilton. 2010. Requiem for a Species: Why We Resist the Truth About Climate Change

Page photograph from Nature News article “Geoengineering can’t please everyone”  doi:10.1038/news.2010.357

Microdocumentaries, Steve Palumbi and ocean acidification

Screen shot 2009-10-04 at 6.18.11 PM

Professor Steve Palumbi of Stanford University is pioneering the use of small ‘to the point’ videos (‘microdocs’) to illustrate important issues that face the ocean.  In this one, he outlines (with superb clarity) the issue of ocean acidification and illustrates why it is such a serious threat to marine ecosystems like coral reefs.  While Steve is using stronger acid than ultimately will be seen in the world’s oceans as they acidify (essentially speeding up the process), he illustrates the key nature of the threat in a way that anyone could understand. Well done – check out Steve’s page for more microdocs on a whole range of environmental topics, including coral bleaching, crown of thorns, marine parks and why it really sucks to be a tuna.

“National targets give virtually no chance of protecting coral reefs”

A study published in Nature Reports Climate Change on 11 June 2009 reports on the consequences of the emission targets being set by countries, including the US and Australia, in the lead-up to the international climate negotiations in Copenhagen in December.

Joeri Rogelj and colleagues conclude, “National targets give virtually no chance of constraining warming to 2 °C and no chance of protecting coral reefs.”


Citing recent publications of Jacob Silverman and colleagues, they note in relation to ocean acidification and coral reefs:

Acid test
While we have focused on global mean temperature increase here, it is increasingly clear that independent of its effect on temperature, growing CO2 concentrations in the atmosphere will also threaten the world’s oceans owing to acidification. The latest research indicates substantial risk to calcifying organisms at atmospheric CO2 concentrations of 450 ppm, with all coral reefs halting their growth and beginning to dissolve at concentrations of 550 ppm. The best Halfway to Copenhagen emissions pathway would result in CO2 concentrations above this level shortly after 2050.

Unless there is a major improvement in national commitments to reducing greenhouse gases, we see virtually no chance of staying below 2 or 1.5 °C. Coral reefs, in addition, seem to have certainly no chance if the work of Jacob Silverman and colleagues is correct.

Could coral reefs close to seagrass be buffered from ocean acidification?

coral1Seagrass meadows have long been known to be highly productive habitats, and as a result producing oodles of oxygen in the midday sun. Anyone who’s ever snorkelled over a seagrass meadow on a sunny day will have seen seagrass leaves furiously bubbling away. This photosynthetic productivity can result in an increase in the pH of the water column (becoming less acidic). This is primarily because CO2 and, thus, its form when dissolved in seawater, carbonic acid, are withdrawn from the water as a substrate for photosynthesis. This results in the production of the bubbling O2. But what are the consequences of such a pH change?

Recent research by the Universities of Dar es Salaam, Tel Aviv and Stockholm published in the Marine Ecology Progress Series (volume 382) and conducted in tropical seagrass meadows of East Africa have investigated the impact of such pH changes.  Semasi et al. revealed that this change in pH can cause localised increases in the rates of calcification and growth of calcareous algae such as Hydrolithon sp., Mesophyllum sp., and Halimeda sp., hence seagrass buffers high acidity (low pH).

As has been debated by ClimateShifts previously, there is increasing evidence that oceans have become more acidic since the start of the industrial era. Recent predictions suggest that oceans could become much more acidic over the next 100 years as a result of increasing CO2 emissions. Current predictions suggest that this will result in (amongst other things) declining reef calcification rates.

Although this study by Semesi et al. shows the effects of seagrass upon algae, the questions on the lips of many reef conservationists will be whether such findings are cross transferable to the calcification of corals. These studies in Zanzibar were small scale, carried out in seagrass mesocosms, and currently only reflect small scale patterns. Whether seagrass productivity can result in larger spatial scale changes that could buffer pH changes on nearby reefs remains to be seen. Maybe the World should be looking at seagrass meadows with greater attention?

Ocean acidification an ‘underwater catastrophe’


‘Climate change is turning our seas acidic, academies warn’ – Reuters News, May 31st 2009

Climate change is turning the oceans more acid in a trend that could endanger everything from clams to coral and be irreversible for thousands of years, national science academies said on Monday.

Seventy academies from around the world urged governments meeting in Bonn for climate talks from June 1-12 to take more account of risks to the oceans in a new U.N. treaty for fighting global warming due to be agreed in Copenhagen in December.

“To avoid substantial damage to ocean ecosystems, deep and rapid reductions of carbon dioxide emissions of at least 50 percent (below 1990 levels) by 2050, and much more thereafter, are needed,” the academies said in a joint statement.

The academies said rising amounts of carbon dioxide, the main greenhouse gas emitted mainly by human use of fossil fuels, were being absorbed by the oceans and making it harder for creatures to build protective body parts.

The shift disrupts ocean chemistry and attacks the “building blocks needed by many marine organisms, such as corals and shellfish, to produce their skeletons, shells and other hard structures”, it said.

On some projections, levels of acidification in 80 percent of Arctic seas would be corrosive to clams that are vital to the food web by 2060, it said.

And “coral reefs may be dissolving globally,” it said, if atmospheric levels of carbon dioxide were to rise to 550 parts per million (ppm) from a current 387 ppm. Corals are home to many species of fish.

“These changes in ocean chemistry are irreversible for many thousands of years, and the biological consequences could last much longer,” it said.

The warning was issued by the Inter-Academy Panel, representing science academies of countries from Albania to Zimbabwe and including those of Australia, Britain, France, Japan and the United States.

Martin Rees, president of the Royal Society, the British science academy, said there may be an “underwater catastrophe”.

“The effects will be seen worldwide, threatening food security, reducing coastal protection and damaging the local economies that may be least able to tolerate it,” he said.

The academies’ statement said that, if current rates of carbon emissions continue until 2050, computer models indicate that “the oceans will be more acidic than they have been for tens of millions of years”.

It also urged actions to reduce other pressures on the oceans, such as pollution and over-fishing.

World Ocean Conference (Part II): Scientists urge world leaders to respond cooperatively to Pacific Ocean threats

picture-387More than 400 leading scientists from nearly two-dozen countries have signed a consensus statement on the major threats facing the Pacific Ocean. The threats identified as the most serious and pervasive include overfishing, pollution, habitat destruction and climate change.

“This is first time the scientific community has come together in a single voice to express urgency over the environmental crisis facing the Pacific Ocean,” said Meg Caldwell, executive director of the Center for Ocean Solutions, who will present the statement on Wednesday, May 13 at 6:30 a.m. U.S. Eastern Time to government officials gathered at the World Ocean Conference in Manado, Indonesia. “The scientific community urges governments to respond now, cooperatively, to these threats before their impacts accelerate beyond our ability to respond.”

The consensus statement, entitled “Ecosystems and People of the Pacific Ocean: Threats and Opportunities for Action,” emerged from a scientific workshop in Honolulu hosted by the Center for Ocean Solutions in collaboration with the International Union for Conservation of Nature (IUCN) and Ocean Conservancy. The workshop was part of a broader effort by the three organizations to challenge countries throughout the Pacific region to improve the health of marine ecosystems by 2020.

In the consensus statement, the scientists warn that if left unchecked, the cumulative impacts of overfishing, pollution and habitat destruction—exacerbated by climate change—could have devastating consequences for coastal economies, food supplies, public health and political stability. These threats affect all members of the Pacific Ocean community, said Stephen Palumbi, director of Stanford University’s Hopkins Marine Station and one of the principal organizers of the consensus statement. “Remarkable similarity exists between the major problems experienced in poor and rich countries alike, in populous nations and on small islands,” said Palumbi, a professor of biology and a senior fellow at Stanford’s Woods Institute for the Environment.

In addition to listing the serious environmental challenges facing the Pacific Ocean, the consensus statement also highlighted a set of potential solutions now being applied and tested at various scales throughout the region. Examples include the establishment of marine protected areas and the creation of economic incentives for activities that promote rather than degrade ecosystem health. “These efforts have shown remarkable success at local scales in maintaining biological and human economic diversity, particularly when applied with adequate levels of regulation and enforcement in place,” said Caldwell, a senior lecturer at Stanford Law School and at the Woods Institute. “These solutions are indicators of hope within an ocean of distress.”

The consensus statement was largely based on a synthesis of more than 3,400 scientific papers on the threats and impacts to the Pacific prepared by the Center for Ocean Solutions. The Pacific Ocean Synthesis provides “a roadmap by which governments might chart a new course of policy for the Pacific region,” said Biliana Cicin-Sain, a professor of marine policy at the University of Delaware and coordinator of the Global Forum on Oceans, Coasts and Islands, a multi-stakeholder network committed to advancing ocean issues within international agreements.

“The impacts of misuse of our ocean resources on our economy, our environment and our community can no longer be ignored,” said Gov. Sinyo Harry Sarundajang of the Indonesian province of North Sulawesi, whose capital Manado is hosting the World Ocean Conference. The governor will convene the event with Caldwell on Wednesday. “We must work together at the regional and transboundary levels to find solutions for improved management of our common ocean.”

The scientific consensus statement and synthesis can be found at the Center for Ocean
Solutions website, Scientists interested in signing the consensus statement can send an email to

Based in Monterey, Calif., the Center for Ocean Solutions is a collaboration of three leading marine science and policy institutions—Stanford University (through its Woods Institute for the Environment and Hopkins Marine Station), the Monterey Bay Aquarium and the Monterey Bay Aquarium Research Institute (MBARI). The center focuses on finding practical, enduring solutions to major challenges facing the oceans.

(Photograph courtesy of Flickr)

A world without fish – what would it take?


A Sea Change – Imagine a World Without Fish” is a recently released documentary film about ocean acidification, the little-known ugly sister of global warming. The film website explains it “… aims not only to educate viewers about the science of our rapidly-changing oceans, but also to engage them on accessible terms.”
The full film was shown to the European Geosciences Union 2009 conference on 27 April 2009, a podcast of which is available here. After a 2 minute introduction, the film lasts for 19 minutes followed by an illuminating question and answer session.

The other CO2 problem – animated adventures into ocean acidification


Take a look at this light-hearted video on a serious subject. This animation on ocean acidification was made by students from the Ridgeway School (Plymouth, UK) and the Plymouth Marine Laboratory – an excellent production!

Ridgeway students have made a short animated film which is being used internationally to highlight the acidification of the world’s seas. Called ‘The Other CO2 Problem’, the film was commissioned by Dr Carol Turley from Plymouth Marine Laboratory, a leading authority on ocean acidification who had seen a previous film (which won a Europe wide film making competition held by Euroceans) made by the students which highlighted the problem of pollution in the seas.

Sixteen students drew up the storyline, designed and made the starring characters from plasticine then filmed the stop frame animation. Seventy other students composed and played the accompanying music

“Hungry Crustaceans Eat Climate Change Experiment”

copepodsThe ‘seeding of the oceans’ with iron as a ‘quick fix’ to climate change has been the subject of much debate over recent years, with some companies going as far as commercialising the selling the concept in exchange for carbon credits. The idea – to seed the surface of the oceans with iron (a trace element essential to photosynthesis that is often a limiting factor in the marine world) in order to stimulate phytoplankton growth, in turn sequestering carbon dioxide from the atmosphere – isn’t entirely new. Over thirteen research groups have trialled iron fertilisation since 1993 to varying degrees of success, although most of these projects have fallen short of the dream of the late oceanographer John Martin back in the late 80’s: “Give me a half a tanker of iron and I will give you another ice age”

After a series of moderate succeses onver the past decade, it seems that the idea of sequestering CO2 in the oceans might truely be dead and buried. Project LOHAFEX, a joint Indo-German group, succeeded in seeding an area of 300km2 with over 6 tonnes of iron, resulting in a doubling of plankton biomass in just two weeks. What the team didn’t factor was the power of the oceans food web. Instead of the plankton bloom undergoing a natural death and sinking to the ocean floor (along with the sequestered CO2), the phytoplankton became an instant food source for hungry copepods, who in turn were consumed by a swarm of larger crustaceans (amphipods – see inset picture).

This ‘grazing effect’ was apparently absent from previous experiments, which instead  stimulated the growth of diatoms. Diatoms differ from most phytoplankton in that they are protected from being eaten by protective shells made of silica. Whilst the experiment did succeed in providing new insights into the dynamics and ecology of plankton, to quote Ken Caldiera “I think we are seeing the last gasps of ocean iron fertilisation as a carbon storage strategy”.

“Carbon emissions creating acidic oceans not seen since dinosaurs”

“The choice to continue emitting carbon dioxide means that we will be an agent of biological change of a force and magnitude exceeded only by the causes of the great mass extinction events. If we do not cut carbon dioxide emissions deeply and soon, the consequences of ocean acidification will stand out against the broad reaches of geologic time. Those consequences will remain embedded in the geologic record as testimony from a civilisation that had the wisdom to develop high technology, but did not develop the wisdom to use it wisely.” – Ken Caldiera (10.03.08)