Attention should turn to nitrous oxide if climate change is to be properly addressed, according to a Brisbane-based member of a Nobel Prize-winning team who says the gas has 300 times the impact of carbon dioxide.
Queensland University of Technology professor Richard Conant was part of the Intergovernmental Panel on Climate Change, which won the 2007 Nobel Peace Prize along with Al Gore.
Professor Conant’s latest research suggests the best way to reduce greenhouse emissions is to improve the way nitrogen fertiliser, which releases nitrous oxide, is applied to crops throughout the world.
Greenhouse gas emissions from agriculture come from two main sources: 38 per cent from nitrous oxide from poor soil fertilisation and 34 per cent from methane from stock.
Professor Conant said the nitrous oxide could be better controlled than methane-emitting pigs and cattle.
“The three greenhouse gases related to agriculture are carbon dioxide, nitrous oxide and methane,” he said.
“They have different impacts on the atmosphere. Now if we say carbon dioxide has an impact of one, methane has an impact of say 21 times.
“Nitrous oxide has an even bigger impact, something like 300 times the impact of CO2.”
The figures represent the ability of a molecule to absorb the long wave energy radiation from the earth.
Nitrous oxide was, per molecule, a bigger destroyer of the cushioning greenhouse environment surrounding the earth, Professor Conant said.
“Nitrous oxide is not the main greenhouse gas, it is just that for every molecule of greenhouse gas, it just absorbs a lot more of the energy from the earth,” he said.
Professor Conant’s latest research suggests it is possible to produce more food and reduce greenhouse gas emissions by improving the way nitrogen fertiliser is applied in developing countries.
Professor Conant, who now works at QUT’s Institute of Sustainable Resources, has used computer modelling to analyse the way nitrogen is applied throughout the world to cereal crops, like maize, rice, wheat, millet and sorghum.
Collectively, these cereals make up about 70 per cent of the world’s food production.
“Literature in this field implies that with greater (nitrogen) fertilisation we can expect that we are going to be less efficient at growing food,” Professor Conant said.
“So there is this fear out there that we are seeing diminishing marginal returns on our nitrogen inputs to the system.”
However, Professor Conant’s research into international cereal crop farming shows that is not the case.
“I think that while in some countries the nitrogen inputs are increasing, the benefits from those nitrogen are not increasing as much in the developing world as they are in the rich world,” he said.
If better food yields could come from improved nitrogen fertilising, Professor Conant said more food could be produced with a lower greenhouse impact.
“By bridging this gap, food production in developing countries can grow more quickly than nitrogen inputs grow in those countries,” he said.
Professor Conant’s research will be housed at the United Nations Food and Agriculture Organisation and used by all member nations.
Source: Forget carbon, this is worse: researcher – Brisbane Times AU
Date: 16 June 2011