Tag Archives: climate change

more on climate change and U.S. farming

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This NPR article says that climate change is allowing North Dakota farmers to switch from wheat to corn.

“Especially the increase in moisture has allowed for better yields and more profit in corn than, say, if we had some of the lesser moisture we had in the ’70s and the ’80s,” Ritchison says.

Corn and soybeans, which also like the moisture, now cover about 15 percent of North Dakota’s cropland, says Ritchison, and the number of acres keeps expanding. The Slabaugh farm is a prime example of corn’s advance. They will plant at least 1,500 acres this year — compared to none 10 years ago.

Changes in weather patterns aren’t the only reason for the move to corn. The crop is also more lucrative: Corn produces much bigger yields per acre than wheat.

All well and good for those farmers, but this doesn’t strike me as an upbeat story in the larger context. If we are in danger of losing productive farmland in many states due to a combination of heat, drought, and groundwater depletion, is it really so helpful that productive farmland in other states is now able to switch from one crop to another? Even if biotechnology helps and yields get higher, it seems like it would be a net loss. This is the United States. What is the story in the tropics, where there is generally less farmland and more people?

you know nothing, snow

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From Wired Science:

The western United States is undergoing a major shift in precipitation patterns. Large swaths of the West that have historically been dominated by snow in the winter months are starting to see a lot more rain instead. A new study that maps out the predominant form of precipitation shows that this trend could result in an average reduction in snow-dominated area of around 30 percent by the middle of this century.

The western US depends heavily on snowpack to sustain its water supply through the dry summertime, but the new research, published in Geophysical Research Letters in July, suggests this may have to change.

Hmm…here’s the abstract of the paper…not quite so sensational sounding although it still clearly says there is going to be a lot less snow:

This approach identifies areas most likely to undergo precipitation phase change over the next half century. At broad scales, these projections indicate an average 30% decrease in areal extent of winter wet-day temperatures conducive to snowfall over the western United States.

climate change, water, and corn

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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

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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

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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.