Some of the most important crops risk substantial damage from rising temperatures. To better assess how climate change caused by human greenhouse gas emissions will likely impact wheat, maize and soybean, an international team of scientists now ran an unprecedentedly comprehensive set of computer simulations of US crop yields. Importantly, the scientists find that increased irrigation can help to reduce the negative effects of global warming on crops, but this is possible only in regions where sufficient water is available. Harvest losses from elevated temperatures of 20 percent for wheat, 40 percent for soybean and almost 50 percent for maize, relative to non-elevated temperatures, can be expected at the end of our century without efficient emission reductions. "The losses got substantially reduced when we increased irrigation of fields in the simulation, so water stress resulting from temperature increase seems to be a bigger factor than the heat itself," says co-author Joshua Elliott from the University of Chicago. This usually increases the water use efficiency of plants since they lose less water for each unit of CO2 taken up from the air. The additional CO2 fertilization in the simulations does not alleviate the drop in yields associated with high temperatures above about 30 C. The comparison of different computer simulations of climate change impacts is at the heart of the ISIMIP project (Inter-Sectoral Impacts Modelling Intercomparison Project) comprising about 100 modelling groups worldwide.
Not only is the environment taking affect on the increase of heat, but so are the crops and agriculture land. The greenhouse gas emissions humans that humans are having a huge part in, is beginning to cause bigger scale problems and needs to be solved. https://www.sciencedaily.com/releases/2017/01/170119084622.htm
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Their routes take them beyond areas that come under the jurisdiction of individual coastal states, and into the high seas. Under international law the high seas, which span 64% of the surface of the ocean, are defined as "the common heritage of mankind". This definition might have provided enough protection if the high seas were still beyond mankind's reach. And high-seas fishing greatly disturbs the sea bed: the nets of bottom trawlers can shift boulders weighing as much as 25 tonnes. A clutch of regional organisations have been set up to try to manage fish stocks in the high seas. By reducing fuel costs, subsidies bring the high seas within reach for a few lucky trawlers, largely from the developed world. As of 2014 less than 1% of the high seas enjoyed a degree of legal protection. So in parallel with efforts to protect wild stocks, another push is needed: to encourage the development of aquaculture, the controlled farming of fish. Whether you’re raising fish in an offshore cage or in a filtered tank on land, you still have to feed them. They have one big advantage over land animals: You have to feed them a lot less. Fish need fewer calories, because they’re cold-blooded and because, living in a buoyant environment, they don’t fight gravity as much.
Overall the research towards environmentally friendly aquaculture farms is growing tremendously. We should not only invest in alternative farms but also aquatic farming to improve land and water species productions. http://www.economist.com/news/leaders/21702196-how-stop-overfishing-high-seas-net-positive?zid=293&ah=e50f636873b42369614615ba3c16df4a Drought struck the Sahel most recently in 2012, triggering food shortages for millions of people due to crop failure and soaring food prices. By replacing vegetative cover's moist soil, which contributes water vapor to the atmosphere to help generate rainfall, with bare, shiny desert soil that merely reflects sunlight directly back into space, the capacity for rainfall is diminished. Another human-caused culprit is biomass burning, as herders burn land to stimulate grass growth, and farmers burn the landscape to convert terrain into farming land and to get rid of unwanted biomass after the harvest season. This can happen because water vapor in the atmosphere condenses on certain types and sizes of aerosols called cloud condensation nuclei to form clouds; when enough water vapor accumulates, rain droplets are formed. To do so, Ichoku and his colleagues used satellite records from 2001 to 2014 -- including data from NASA's Moderate Resolution Imaging Spectroradiometer and the Tropical Rainfall Measurement Mission -- to analyze the impact of fires on various water cycle indicators, namely soil moisture, precipitation, evapotranspiration and vegetation greenness. The results so far show only a correlation between fires and water cycle indicators, but the data gathered from the study is allowing scientists to improve climate models to be able to establish a more direct relationship between biomass burning and its impacts on drought.
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