Crop yields in a geoengineered climate

A research team at Stanford University, led by Dr. Julia Pongratz, finds that solar-radiation geoengineering in a high-CO2 climate generally causes crop yields to increase, largely because temperature stresses are diminished while the benefits of CO2 fertilization are retained.

The team adds that, nevertheless, possible yield losses on the local scale as well as known and unknown side effects and risks associated with geoengineering indicate that the most certain way to reduce climate risks to global food security is to reduce emissions of greenhouse gases.

Paper: Crop yields in a geoengineered climate
Press release: Geoengineering and global food supply

Global Warming Action Plan

All nations should commit to effective action to deal with climate change. Nations should each be able to decide for themselves how to do this, provided they each meet agreed targets independently and genuinely (i.e. without buying or fabricating offsets or credits, domestically or abroad). Where necessary, border adjustments can help ensure that commitments are indeed met. Some policies may aim to reduce emissions in one area, while causing emissions elsewhere. As an example, biofuel may reduce emissions of carbon dioxide (CO₂) in transport, while increasing agricultural emissions, reducing forests and diverting crop, water and energy from better use. It is important for nations to each achieve results on each of the following points, without achievements in one area being counterproductive elsewhere. It is therefore recommended to take an approach that seeks results on each of the following points.

  Part 1. Reduce oceanic and atmospheric CO₂

Target: Ensure that atmospheric CO₂ levels do not exceed 400 ppm over the next few decades, while aiming for a longer term target of 350 ppm. James Hansen, NASA's top climate scientist, says in Target CO₂: Where Should Humanity Aim? that atmospheric CO₂ should be reduced to 350 ppm. To achieve this target, several policies will need to work in parallel with each other. 

  1.1. Dramatic cuts in CO₂ emissions In many cases, dramatic cuts in CO₂ emissions can be achieved merely by electrifying transport and shifting to generation of energy by clean facilities such as solar panels and wind turbines. Each nation should aim to reduce their CO₂ emissions by a minimum of 8% per year over the next ten years, based on their 2009 emissions, and by 80% by 2020. 

  1.2. Carbon must also be actively removed from the atmosphere and the oceans A study at the University of Calgary concludes that, even if we completely stopped using fossil fuels and put no more CO₂ in the atmosphere, the West Antarctic ice sheet will still eventually collapse (by the year 3000), causing a global sea level rise of at least four meters. This means that - apart from reducing emissions - there should be additional efforts to remove CO₂ from the atmosphere and the oceans, in order to get CO₂ down to levels as pictured on the above graph. Carbon is naturally removed from the atmosphere and the oceans by vegetation, so it makes sense to protect forests and encourage their growth. There are ways to reduce ocean acidification, such as by adding lime to seawater, as discussed at other posts of this geoengineering blog and at this geoengineering group. Carbon capture from ambient air and pyrolysis of surplus biomass with biochar burial are some of the most promising methods to further remove carbon from the atmosphere. Biochar can also help with afforestation and prevent deforestation and land degradation. Funding of carbon air capture could be raised through fees on jet fuel. All nations should commit to such initiatives — care should be taken that emission reductions are not substituted by carbon removal or vice versa. 

  Part 2. Short-term action 

The Arctic sea ice acts as a giant mirror, reflecting sunlight back into space and thus keeping Earth relatively cool, as discussed in this open letter. If this sunlight instead gets absorbed at higher latitudes, then feedback effects will take place that result in much higher temperatures, in a process sometimes referred to as Arctic amplification of global warming. The IPCC didn't take such feedback into account in AR4. A study that used 2007/2008 data as starting point predicts a nearly sea ice free Arctic in September by the year 2037, some predict an even quicker demise. A study by by National Center for Atmospheric Research (NCAR) scientist Jeffrey Kiehl found that carbon dioxide may have at least twice the effect on global temperatures than currently projected by computer models of global climate. Melting of ice sheets, for example, leads to additional heating because exposed dark surfaces of land or water absorb more heat than ice sheets. Albedo change is only one of a number of feedback processes. A rapid rise of Arctic temperatures could lead to wildfires and the release of huge amounts of carbon dioxide and methane that are now stored in peat, permafrost and clathrates, which constitutes further feedback that could cause a runaway greenhouse effect. Heat produced by decomposition of organic matter is yet another feedback that leads to even deeper melting.    

  2.1. Reduce methane and nitrogen oxide emissions Reductions in the emissions of methane and nitrogen oxide can be achieved by a change in diet, improved waste handling and better land use. Effective policies such as feebates can impose fees on nitrogen fertilizers and livestock products, while using the revenues to fund pyrolysis of organic waste. 

  2.2. Emissions of other pollutants than conventional greenhouse gases should also be reduced Both the Kyoto Protocol and the IPCC have focused much on reducing CO₂ emissions, as well as other conventional greenhouse gases such as methane and nitrogen oxide. Melting in the Arctic carries the risk of huge additional emissions from peat, permafrost and clathrates, which calls for more immediate mitigation action. All nations should therefore commit to short-term mitigation — long-term mitigation efforts should not be substituted by short-term mitigation or vice versa. As this NASA study points out, for more effective short-term impact, drastic cuts should also be made in other pollutants, such ozone, soot and carbon monoxide. This is further illustrated by the image on the right that shows what causes most radiative forcing (W/m²) when taking into account all pollutants over a 20-year period, from a study published in Science. Reducing short-lived pollutants could significantly reduce warming above the Arctic Circle, finds a study published in Journal of Geophysical Research. A relatively cheap way to achieve such cuts is by encouraging the use of solar cookers and rechargeable batteries to power LED lights. Many types of equipment and appliances can also be powered this way, even when batteries are recharged by hand cranking or pedaling. Electrification of road transport is a crucial part of short-term action, as illustrated by the image, while generation of energy from clean facilities such as solar panels and wind turbines (as also discussed under part 1.1.) will further contribute to reductions in short-lived pollutants. Furthermore, reductions in short-lived pollutants can be achieved by preservation of forests, which justifies financial assistance by rich countries. As said, such assistance should not be used by rich nations as a substitute for domestic action — action is also required domestically by each nation, on all points. The desired shifts can often best be accomplished locally by budget-neutral feebates, i.e. fees on local sales of fuel, engines and ovens, each time funding the better local products, as illustrated by the image below. 

  2.3. Furthermore, consider ways to reflect more solar radiation back into space Discussions of ways to reflect solar radiation can be found at other posts of this geoengineering blog and furthermore at this geoengineering group. 

  Part 3. Adaptation 

 Look at policies that can help people, flora and fauna adapt to climate change. Rich nations are urged to give financial assistance to poorer nations, as well as to facilitate technology transfer, including by preventing that intellectual property protection acts as a barrier to such transfer. 

  3.1. Prepare for extreme weather events Look at safety issues from the perspective of a changed world. Prepare for hailstorms, heavy flooding, severe droughts, wildfires, etc., and grow food that fits such weather patterns best. 

  3.2. Preserve biodiversity Protection of rain forests is well covered in the media. Biodiversity can be further preserved by means of seed banks, parks and wildlife corridors. 

  3.3. Vegetate Fresh water supply and food security require extensive planning, such as selection of best crop. Build facilities for desalination both for fresh water in cities and to irrigate and vegetate deserts and other areas with little vegetation.

image from: Towards a sustainable Economy Leading global warming experts are invited to contribute comments and thoughts as to what constitutes an effective global warming action plan

Open Letter to Major Economies Forum on Energy and Climate

Forum Participants,

We, a group of scientists, researchers and other people sharing a strong background and interest in climate change, are concerned that the Forum's sole focus will be on the politics of energy, as seems confirmed by the name of the Forum.

We believe that the scientific evidence strongly suggests that the approach to the climate change problem should be as broadly based as possible. As such, this should include the following four parts:
Part A: Emissions reduction
Part B: Carbon stock management
Part C: Heat transfer and radiation management
Part D: Adaptation

We note that there is little or no funding for research and testing of geoengineering methods (in Part B and Part C). These should be urgently considered as part of a comprehensive approach to climate change.

Signatories:
- John Nissen (jn@cloudworld.co.uk)
- Andrew Lockley (Former director of Friends of the Earth ENWI - UK)
- Peter Read (Hon. Research Fellow, Massey University Centre for Energy Research - NZ)
- Bill Fulkerson (Senior Fellow, Institute for a Secure and Sustainable Environment, University of Tennessee)
- Dan Wylie-Sears
- Eugene I. Gordon
- John Gorman (MA (Chartered Engineer MIMechE, MIET - UK)
- Jim Woolridge (former Climate and Energy Campaigner, Earthwatch/Friends of the Earth, Ireland)
- Sam Carana (contributor to feebate.net - sam.carana@gmail.com)

References:
White House Announcement of Major Economies Forum (MEF)
White House Announcement of Mexico MEF Meeting
Department of State Annoucement of MEF
Open letter to Dr Rajendra K. Pachauri, IPCC chair (Gather)
Open letter to Dr Rajendra K. Pachauri, IPCC chair (Geo-engineering)
Open Letter to Major Economies Forum Participants (background)

Open letter to Dr Pachauri

Climate Congress, Copenhagen, 10-12 March, 2009 

Open letter to Dr Rajendra K. Pachauri, IPCC chair

Dear Dr Pachauri,

The Climate Congress presents an important opportunity to present all facets of the current situation, explore the ramifications, and suggest appropriate actions. The aim must be, as far as possible, to address the threat of a disastrous multi-metre rise in sea level and catastrophic multi-degree rise in temperature – whenever they might occur.

We would like to suggest a rather simple division of the problem/solution domain:

Part A: Emissions reduction

About: Reducing emissions of greenhouse gases into the atmosphere.

Target: Achieve near-zero carbon economies throughout the world by end century.

Difficulties: International agreement, life-style changes, high cost.

Rationale: Long-term sustainability.


Part B : Carbon stock management

About: Removing CO2 from the atmosphere by various means.

Target: Reduce levels below 350 ppm over next three decades.

Difficulties: May involve change in agricultural practice, worldwide. Side-effects may be difficult to anticipate.

Rationale: Reduce CO2 climate forcing below its current level, halt ocean acidification and protect carbon sinks.


Part C : Heat transfer and radiation management

About: Mainly about albedo engineering and solar radiation management.

Priority target: Cool the Arctic sufficient to halt retreat of Arctic sea ice within three years.

Difficulties: Seen as tampering with the environment, and therefore intrinsically dangerous; but cost is low and side-effects should be manageable.

Rationale: Reduce risk of massive methane discharge and stabilise the Greenland ice sheet.

International focus has been almost entirely on Part A until recently, when it has been realised that: 

(1) it is proving extremely difficult to achieve reductions; 

(2) the current trend is towards IPCC’s worst case scenario; 

(3) lifetime of CO2 had been under-estimated – even if anthropogenic greenhouse gases could be stopped overnight, the existing gas levels will live on in the atmosphere for centuries, causing the global temperature to continue to rise many degrees; 

(4) global warming of more than 2 degrees could be disastrous; 

(5) tipping points could be reached much sooner than expected. It is generally recognised that the underlying primary cause of global warming is the excess of CO2 in the atmosphere. If emissions reduction can’t reduce it quickly enough, then we have to resort to some form of geoengineering – or more specifically carbon stock management – see Part B. 

Furthermore, ocean acidification is becoming dangerous, and this can only be tackled by removing CO2 from the atmosphere. So, within a decade or two, carbon stock management could become essential, and we should be doing large-scale experimentation now. 

But the actions of Part A and Part B cannot prevent tipping points driven by positive feedback on temperature. Emissions reduction and carbon stock management cannot produce a cooling effect – certainly not on the time-scales we are talking about. We have to resort to other kinds of geoengineering, hence Part C. 

As regards tipping points, our perception of the situation has changed fundamentally since the dramatic retreat of Arctic sea ice in September 2007. The IPCC had chosen to ignore potential tipping points, as being too difficult to model or lacking reliable data. 

But now some experts are talking about possible summer disappearance of sea ice within a decade [1], and this possibility is even mentioned in the introduction to Session 1 of the Congress [2]: “Sea ice is changing and the sea ice in the northern polar ocean has retreated in the last few years and might totally disintegrate during the next decade.” Sea ice disappearance will accelerate Arctic warming which could trigger the release of vast amounts of methane from permafrost (leading to many degrees of global warming) and/or destabilise the Greenland ice sheet (leading to many metres of sea level rise). 

There now appears no other possibility to save the Arctic sea ice than to cool the Arctic region, by reflecting more sunlight back into space. There are two prime candidates for this: stratospheric sulphate aerosols and marine cloud brightening [3]. The former involves the injection of a H2S or SO2 high in the stratosphere, where it reacts to form microscopic droplets of sulphuric acid which scatter sunlight efficiently. This mimics the effect of a volcano like Pinatubo, which cooled the planet for two years from its sulphur emissions into the stratosphere. The latter – the brightening of marine clouds – involves producing a very fine spray of sea water from ships which sail underneath low-lying cumulus clouds, such that some of the spray wafts upwards, brightening the clouds and reflecting light back into space. 

Modeling suggests that each of these cooling technologies should be effective, affordable, fast acting, easily reversible and reasonably safe. If we can save the Arctic sea ice, then we may be able to avoid other tipping points such as the methane release from permafrost. Such action buys time while we reduce CO2 levels and avoid other catastrophes such as from ocean acidification. On the other hand, if we do not act with the necessary urgency, we may soon find ourselves beyond the point of no return: doomed both to many metres of sea level rise and to spiraling temperatures, way above 6 degrees this century – temperatures for which the very survival of our civilization would be in question. 

- John Nissen Email: jn@cloudworld.co.uk for correspondence 

- Stephen Salter Professor of Engineering, University of Edinburgh John Latham http://www.mmm.ucar.edu/people/latham/ 

- Oliver Wingenter Professor of Atmospheric Chemistry and Climate Change, New Mexico Institute of Mining and Technology 

- Peter Read Hon. Research Fellow, Massey University Centre for Energy Research 

- Andrew Lockley, London UK Former director of Friends of the Earth ENWI 

- John Gorman MA (Cantab), London, UK 

- Sam Carana, contributor to feebate.net sam.carana@gmail.com

References:

[1] Climate Safety report, which can be downloaded from: 

http://climatesafety.org/

[2] Climate Congress, Session 1, in: 

http://climatecongress.ku.dk/programme/sessions06.03.2009.pdf

[3] Solar Radiation Management: 

http://en.wikipedia.org/wiki/Solar_radiation_management