Tag Archives: climate change

climate change, water, and corn

Here are a couple stories on U.S. corn yields:

From the “Risky Business Project“:

Shifting agricultural patterns and crop yields, with likely gains for Northern farmers offset by losses in the Midwest and South.

  • As extreme heat spreads across the middle of the country by the end of the century, some states in the Southeast, lower Great Plains, and Midwest risk up to a 50% to 70% loss in average annual crop yields (corn, soy, cotton, and wheat), absent agricultural adaptation.

  • At the same time, warmer temperatures and carbon fertilization may improve agricultural productivity and crop yields in the upper Great Plains and other northern states.

  • Food systems are resilient at a national and global level, and agricultural producers have proven themselves extremely able to adapt to changing climate conditions. These shifts, however, still carry risks for the individual farming communities most vulnerable to projected climatic changes.

From Ceres:

  • 87% of irrigated U.S. corn is grown in regions with high or extremely high water stress, meaning there is limited additional water available for expansion of crop irrigation. The most vulnerable regions are in Nebraska, Kansas, California, Colorado and Texas.
  • 27% of rainfed corn is grown in regions with high or extremely high water stress, meaning that there is limited water available should climate change make irrigation necessary. The most vulnerable regions are in Illinois, Wisconsin and Michigan.
  • Twelve ethanol refineries above the High Plains aquifer – with nearly $1.7 billion in annual corn ethanol production capacity – are sourcing corn in areas experiencing cumulative declines in groundwater levels. Six of these refineries are in regions of extreme water-level decline (between 50-150 feet).

To me, this sounds like a lot of today’s productive farmland may not stay that way due to a combination of higher temperatures and drought. Can we really open up enough farmland and/or increase yields in “Northern States” to make up the difference? I suppose maybe there are areas of Canada that could go from ice-covered to prime farmland, as long as they stay wet enough.

U.S. Drought Monitor

20140729_CA_trd

According to the United States Drought Monitor, the drought in California is getting pretty alarming.

mounting evidence from reservoir levels, river gauges, ground water observations, and socio-economic impacts warrant a further expansion of exceptional drought (D4) into northern California. For California’s 154 intrastate reservoirs, storage at the end of June stood at 60% of the historical average. Although this is not a record for this time of year—the standard remains 41% of average on June 30, 1977—storage has fallen to 17.3 million acre-feet. As a result, California is short more than one year’s worth of reservoir water, or 11.6 million acre-feet, for this time of year. The historical average warm-season drawdown of California’s 154 reservoirs totals 8.2 million acre-feet, but usage during the first 2 years of the drought, in 2012 and 2013, averaged 11.5 million acre-feet.

Given the 3-year duration of the drought, California’s topsoil moisture (80% very short to short) and subsoil moisture (85%) reserves are nearly depleted. The state’s rangeland and pastures were rated 70% very poor to poor on July 27. USDA reported that “range and non-irrigated pasture conditions continued to deteriorate” and that “supplemental feeding of hay and nutrients continued as range quality declined.” In recent days, new wildfires have collectively charred several thousand acres of vegetation in northern and central California. The destructive Sand fire, north of Plymouth, California—now largely contained—burned more than 4,000 acres and consumed 66 structures, including 19 residences.

 

 

the urban carbon cycle

This article from Landscape and Urban Planning looks at carbon emissions and carbon sequestration in Beijing:

During the study period, carbon sequestration only offset 2.4% of carbon emission, indicating a serious imbalance of the city’s carbon metabolism. The city’s core built-up area expanded along eight axes, and its form fluctuated between simpler and more complex. From a small-scale perspective, the spatial pattern mainly showed expansion and aggregation of patches with high carbon emission and shrinkage and fragmentation of patches with high carbon sequestration.

I think this sort of study is useful as we think about what it would mean for cities to be truly sustainable either within their own boundaries or in the context of the larger landscape. 2.4% doesn’t sound like much, but if that is the answer with no system-level planning or management, could it be boosted to 5% or 10% with a more systematic approach to green infrastructure? The rest of the landscape (farms, protected forests, grasslands, and wetlands, and bodies of water) would do its share. Finally, technology would have to make up the remaining gap, if we really want to one day get to carbon neutral or even begin to role back the damage we have done to the atmosphere and oceans.