Blog - new kid on the block - geoengineering and the IPCC








The past few months represent an important step forward for our understanding of climate change, with the Intergovernmental Panel on Climate Change (IPCC) publishing two eagerly-awaited contributions to its Fifth Assessment Report (see In Verba commentary here and here). With the third and final thematic report launched yesterday, one distinction between this set of reports and their 2007 predecessors is clear: the conspicuousness of geoengineering.

‘Geoengineering’ refers to a suite of techniques to reduce global warming by intervening in the Earth’s climate system. It can involve removing carbon dioxide from the atmosphere (carbon dioxide removal, or CDR), or reflecting a small proportion of sunlight back into space (solar radiation management, or SRM).

The first instalment in the IPCC’s Fifth Assessment ReportThe Physical Science Basis – raised media hackles when it devoted the final paragraph of its Summary for Policymakers (arguably the most widely read output) to geoengineering. It states:

‘Methods that aim to deliberately alter the climate system to counter climate change, termed geoengineering, have been proposed. Limited evidence precludes a comprehensive quantitative assessment of both Solar Radiation Management (SRM) and Carbon Dioxide Removal (CDR) and their impact on the climate system… CDR and SRM methods carry side effects and long-term consequences on a global scale’.

To some, this mention was justifiable (‘intellectual honesty’ even) in light of the report’s overriding message – that climate change is happening, that we’re causing it, and that even if emissions ceased altogether we’d still be committed to centuries of warming. To others, however, this denouement in the Summary for Policymakers (as opposed to text buried in the main report) assigned ‘premature legitimacy’ to the issue.

Discussions of geoengineering in the second instalment Impacts, Adaptation and Vulnerability – were peppered throughout the main report and sparked less controversy. Chapter 19 (Emergent Risks and Key Vulnerabilities) provided the most detailed analysis. Though as the title suggests, risks rather than any potential benefits were the focus. The chapter summary states:

‘In addition to providing potential climate change abatement benefits, geoengineering poses widespread risks to society and ecosystems. For example, in some model experiments the implementation of Solar Radiation Management [SRM] for the purpose of limiting global warming leads to ozone depletion and reduces precipitation. In addition, the failure or abrupt halting of SRM risks rapid climate change’.

Geoengineering was also described as ‘emergency mitigation’ and as something that could receive more attention and resources in the event of a climate threshold being crossed.

The third reportMitigation of Climate Change, published yesterdaysimilarly writes geoengineering into its pages. And once again, the tone is one of risk and uncertainty. The Summary for Policymakers states that the more ambitious mitigation scenarios:

‘typically rely on the availability and widespread deployment of BECCS and afforestation in the second half of the century. The availability and scale of these and other Carbon Dioxide Removal (CDR) techniques and methods are uncertain and CDR technologies and methods are, to varying degrees, associated with challenges and risks’.

BECCS, which stands for bioenergy with carbon capture and storage, involves burning biomass (trees, plant waste or woodchips) to generate electricity, capturing the carbon produced by burning, and then injecting that carbon into geological reservoirs. Like all geoengineering techniques, BECCS is controversial. And while the media fallout remains to be seen (the full report is yet to be finalised), environmental concerns have already been raised .


Five years on from the Royal Society’s report, Geoengineering the climate: science, governance and uncertainty, it’s encouraging to see that an issue previously shied away from in political discussions of climate change is now being acknowledged.

With interest in geoengineering growing, the IPCC reminds us that the time is ripe to establish the norms and governance mechanisms to ensure that any geoengineering research that proceeds is safe, ethical and subject to appropriate oversight and independent evaluation.

This is a view proffered by the Solar Radiation Management Governance Initiative (SRMGI) – which comprises the Royal Society, Environmental Defense Fund, and TWAS, the world academy of sciences – as it strives to foster inclusive, interdisciplinary and international dialogue on SRM.

But the IPCC’s engagement in this dialogue is no reason to get carried away. As SRMGI’s Alex Hanafi reminds us here, geoengineering remains (for now at least) a marginal issue. And key messages from the Fifth Assessment Report and SRMGI’s 2011 report alike should not be lost: we’re causing dangerous changes to our climate, and reducing greenhouse gas emissions should remain a global priority. The new kid on the block should not distract us from the old guard.

  • Parminder Singh

    I come from the Far East. Seems to me there is no proper consideration for “nature” friendly geoengineering techniques possibly the reason why it creates a fright for fellow earthians. I am exploring enhanced weathering with olivine which is abundant in many parts of Asia and can be easily mined. 1) delivering salt sprays with fine olivine particles (coated white if necessary) to form marine
    clouds and/or artificial snow, 2) delivering particles of large sizes inside wave
    sinks, maelstroms (natural whirlpools) to reduce its size and reduce ocean acidification
    and 3) distributing olivine dust into the atmosphere from the tip of
    wind turbine blades.

  • Just as the term “global warming” proved to be stupidly misleading regarding the effects of anthropogenic CO2 on the world so too is the term “geoengineering.” Both terms were meant to be “spin mastering” tricks and they have proven to be just so.

    If we talk honestly about “geoengineering” we must put first and foremost all of agriculture which surely is the most extensive and intensive engineering of this planet ever. Following that is the use of concrete, ashphalt, and the variety of building materials that go into our human infrastructure. Perhaps, and just perhaps, space borne sunshades might, if they were not so impossibly and economically far fetched might qualify as a new form of geoengineering.

    As for CO2 repurposing technologies this is something that I can speak to from a position of expertise.

    Surely what the world needs to do is pursue better courses of action to repurpose CO2 from it’s harmful form into better forms. I’ve done this since the 1970’s when I founded a treeplanting company that went on to plant hundreds of millions of trees each and every one made possible by the repurposing of CO2. More recently I have done this by replenishing and restoring a large ocean pasture in the N. Pacific in 2012, some tens of thousands of square kilometers in size.

    One result in the ocean was last falls largest catch of salmon in history in the near-by state of Alaska. Our work repurposed millions of tonnes of CO2 into hundreds of millions of salmon. A small part of that bountiful catch has now been purchased by US Food Aid programs and is on the way to feed hungry children. Here’s a link to learn more

    The same methods can replenish and restore the ocean pastures in many regions of the world where individual ocean pasture restoration projects will repurpose millions of tonnes of CO2 to bring hundreds of millions of fish into the nets of fishermen and into the mouths of people. Well maybe a few lol cats as well.

    Around the world ocean pastures collectively restored will repurpose a billion tonnes of CO2 into a billion fish to feed the worlds hungry.

    Now if this work must be spin mastered by fabricating a straw man called “geoengineer” then the question that ought to be asked is why would anyone want to prevent hungry people from being fed nutritious food at incredibly low cost.

    • Eugene Gordon

      This is a good writeup but it truly misses the key point. No one has proven that CO2 is an important greenhouse gas and that additional CO2 in the atmosphere is responsible for significant warming. The best that can be said about CO2 global warming is that it is an attractive but unproven hypothesis. But if not CO2 warming then what? The answer is there of all to see and we ignore it. There is a solid, uncontested record of warm spells that occur roughly every 1000 years, the last one from 1000 to 1450 AD.Greenland was warmer than now. I will say the Vostok record and if you interested look it up. ~400 warm cycles have been recorded over 400,000 years from ice records by Russian researchers. We are currently experiencing the next cycle. Pacific mud records support this result. With a proven, uncontested record of periodic warm cycles we don’t need CO2.