Feed the World with Smart Farming  (continues from page 1)

        The authors forecast not only the impacts if current trends continue, but how alternative strategies can meet the future food demand with less land clearing and environmental impacts.

        If current trends continue in agriculture, the poorest nations will meet the need for food by clear-cutting more land to put it under cultivation. The wealthiest nations will likely follow pathways of improving fertility on existing lands and boosting yields through advances in technology, as they have done up to now.

        We examine here alternatives to meet the world's demand for crops in 2050, without considering changes in dietary practices. In group A nations, yields are up to three times higher per hectare of land than in the poor nations of groups F and G. Clearly, one solution is to transfer technologies and practices that yield more food from the same land to the poor nations. That reduces pressure to clear wild land, with its many impacts on the environment.

___ More intense application of nitrogen fertilizers can also improve future yields without depending on better technologies. But by maintaining fertilizer application at the same intensity as now, or even less, yields would still increase 50% or more by 2050 through continuing improvements in technology, or better, transfers of technology to poorer nations.

        If the world chooses a policy of avoiding the clearing of new land, yields can increase more than 50% through ambitious transfers of farming technologies and practices. In that scenario, it is possible to get the same yields even if 3 to 5 times less land were cleared, if less developed nations adopt the practices that led to high yields in the developed nations.

Climate impact. Clearing land for agriculture, cultivating it, and making and using fertilizer all release greenhouse gases, especially CO2. Tilman and Clark assert that boosting the application of nitrogen fertilizers in less developed nations will reduce, not increase, the emission of such gases, contrary to what we expect. This is because the pressure to clear new land would be dramatically scaled back. They predict lower GHG emissions from agriculture in 2050 than actually occurred in 2005, if production of nitrogen fertilizers is maintained at the current level. Avoiding deforestation would reduce the GHG emissions by three times more than the GHG increases that result from more intense fertilizer use.

Conclusion. The future demand for Calories can best be met by ambitiously transferring techniques for boosting crop yields from wealthy nations to the least developed nations, rather than to continue current agricultural trends distinctive to each group of nations. By adopting the techniques for boosting soil fertility from the wealthy nations, developing nations would not need to clear new lands for planting. The developed world would not apply nitrogen fertilizers ever more intensively on their own farmland, as they now do, but rather deliver more fertilizers or more technology and know-how to the nations that need it most. In some scenarios, global emission of greenhouse gases from the production of food could actually decrease.

 CITATIONS                                                                            Top

1. "Global food demand and the sustainable intensification of agriculture", by David Tilman, C. Balzer, J. Hill, and B. Befort (2011). Proceedings of Nat. Academy of Sciences, v. 108, 20260--20264, Dec. 13, 2011.

2. In the United States the Calorie (with capital C), commonly used in nutrition, equals 1000 calories (with small c) used in science. A Calorie is also called a kilocalorie. We follow the American usage here.

NEXT: Causes of California Drought

Return to Home Page


Warmest Year Ever: 2014

        The year 2014 is on track to be the warmest ever observed for the world and for Europe. The World Meteorological Organization (WMO) confirmed this on December 3. If last month, December continues the warm trend of previous months, then 2014 will be warmer than all previous record years of 2010, 2005, and 1998.

        “Fourteen of the fifteen warmest years on record have all occurred in the 21st century,” said WMO Secretary-General Michel Jarraud. “There is no standstill in global warming.”

        “What we saw in 2014 is consistent with what we expect from a changing climate. Record-breaking heat combined with torrential rainfall and floods destroyed livelihoods and ruined lives. What is particularly . . . alarming this year are the high temperatures of vast areas of the ocean surface.

        “Record-high greenhouse gas emissions and associated atmospheric concentrations are committing the planet to a much more uncertain and inhospitable future.”

        The temperature of the sea surface this year is the highest ever observed in the 135-year record, according to the US National Oceanic and Atmospheric Administration (NOAA), in its State of the Climate Report this December. This results from seven months (May to November) of elevated temperatures. About 93% of the excess energy trapped in the atmosphere by greenhouse gases from fossil fuels ends up in the oceans. The amount of heat that the oceans hold is key to understanding climate trends.

        Atmospheric levels of carbon dioxide (CO2), methane (CH4), and nitrous oxide reached new highs in 2013 (we still await reports for 2014.) Levels of CO2 reached 396 parts per million (ppm), which is 42% above the levels of the pre-industrial era. Methane levels also reached a new high, at 253% of the pre-industrial level. Since 1990, according to NOAA's Annual Greenhouse Gas Index, the so-called “radiative forcing” of the Earth by greenhouse gases jumped 34%, or about one-third. Radiative forcing measures the excess of energy coming into the Earth compared to the energy leaving the Earth.                                                             Top

Next story: Causes of the California Drought

Return to Home Page