The Climate Change Act of 2008 committed the UK to lowering its greenhouse gas (GHG) emissions to 80% of their 1990 levels by 2050, and led to the establishment of the Committee on Climate Change. Agriculture contributes some 8% of these GHGs, mainly as nitrous oxide (54%) and methane (37%), with carbon dioxide itself contributing just 9%. Nitrogen fertilisers and livestock slurry are mainly responsible for the first of these, and livestock (and some paddy fields) for the second. As part of the response to the Global Food Security agenda (pdf), a sustainable intensification of agriculture has been widely advocated, for instance in the Royal Society ‘Reaping the Benefits’ report and the Foresight Global Food and Farming futures document. However, this intensification cannot be at the expense of extra GHG emissions, and I was pleased to attend a very useful Discussion meeting at the Royal Society on Reducing Greenhouse Gas emissions from agriculture. The full conclusions and papers will be published later in the year, but some facts are worth noting. First of all, the numbers are large: 50-700 t/ha of carbon are already stored in soils, from deserts to peatlands, and while the UK has only 1% of the relevant world land area, we can and should demonstrate intellectual and practical leadership. The world’s net gross primary productivity (GPP) from photosynthesis is ca 120 Pg C/y, with net primary productivity (NPP) about half that, while fossil fuel emissions amount to ‘just’ 8 Pg C/y. Secondly, there are huge ranges for ostensibly similar things, whether the yield of wheat in t/ha (at least a 2-fold range in similar conditions) or methane emissions from beef cattle (8-fold, depending o the style of husbandry), implying substantial benefits to be had from sharing existing best practices. A useful report (pdf) summarises options for mitigation (also known as abatement), using Marginal Abatement Cost Curves.
Of course, fixing atmospheric carbon dioxide is important for our strategy in bioenergy and industrial biotechnology. Indeed, according to Jeremy Woods, recent estimates of the potential of bioenergy are very encouraging. We could probably use 3M ha in the UK (out of 11M). With a 5-10% compound annual growth rate (CAGR – and 2005-9 showed a 20% CAGR), biomass could deliver 200-1000EJ by 2050 (1000 EJ being the total amount of energy used in the world right now). Biofuels production in 2009 was 76Bn L, equivalent to 2.17 EJ, amounting to 3% of world transport energy and 0.5% of global primary energy. The maximum efficiency of photosynthesis is considered to be some 4.6% (C3 plants) to 6% (C4 plants), but in practice typical yields (on the basis of the light initially absorbed) are ~ 1% at best, so there is still plenty to play for.
A widespread consensus, and a view I have been seeking to promote, was that carbon sequestration in soil could indeed show considerable promise. On a related note, the Economist had a very nicely done analysis of how we are to feed 9Bn people
I also attended an interesting meeting of the TGAC Trustee Board, and was able to catch up with the very extensive list of projects that have already been completed or are in the pipeline.
It is in our collective interest to demonstrate the benefits of science funding, and while there is voluminous evidence that it attracts a massive return on investment, this has historically been acquired in a rather ad hoc manner. There was a very nice Summary of a major US project called STAR METRICS that is designed to do this more systematically. Many of the methods involved are likely to benefit from those being devised for ‘dealing with data’ more generally, and an excellent eponymous online collection of papers (including articles on visualisation and on metaknowledge – our knowledge about knowledge) summarises some of the modern approaches. A related paper estimates the world’s capacity in 2007 to store (~290Ebytes), communicate (~2000 Ebytes) and compute information (~1 EFLOP) on ‘general purpose’ computers, noting that it is the transfer of information, more than its storage or our overall computational abilities, that is becoming most limiting.
The online availability of all kinds of data, related to our data sharing policy, makes it possible to mine such data in useful and interesting ways. A pertinent paper that caught my eye (based on ideas from polypharmacology) thereby discovered a number of novel agents.
- Evans JA, Foster JG: Metaknowledge. Science 2011; 331:721-725.
- Fox P, Hendler J: Changing the equation on scientific data visualization. Science 2011; 331:705-708
- Hanson B, Sugden A, Alberts B: Making data maximally available. Science 2011; 331:649
- Hilbert M, López P: The World’s Technological Capacity to Store, Communicate, and Compute Information. Science 2011 (online, subscription only)
- Lane J, Bertuzzi S: Measuring the results of science investments. Science 2011; 331:678-680
- Various: Dealing with data. Science 2011; 331: 692-729. Freely available with registration
- Yabuuchi H, Niijima S, Takematsu H, Ida T, Hirokawa T, Hara T, Ogawa T, Minowa Y, Tsujimoto G, Okuno Y: Analysis of multiple compound-protein interactions reveals novel bioactive molecules. Mol Syst Biol 2011; 7:472
- Zhu XG, Long SP, Ort DR: Improving photosynthetic efficiency for greater yield. Annu Rev Plant Biol 2010; 61:235-261