An international research team says monsoon storms in the Southwest have become less frequent but more intense, bringing more extreme wind and rain to central and southwestern Arizona than just a few decades ago.
The study, led by scientists with the University of Arizona, compared precipitation records from 1950 to 1970 with data from the 1991-2010 period to verify their climate model, scaled down to capture changes at a resolution of 1.5 square miles. At that level of detail the changes over time became apparent, while models using a 10 square mile grid aren’t able to accurately recreate the precipitation trends. Continue reading “Is global warming changing the Southwest monsoon?”→
Study tracks underground flows of water from melting ice
Glaciers are not only important sources of surface water, they also help recharge aquifers as they melt. That role in replenishing underground water reservoirs has been quantified in a new study published recently in Geophysical Research Letters, a journal of the American Geophysical Union.
The research was done in Alaska, where both scientists and residents are reporting increased river discharges in summer and winter. The changes in flowes have implications on river travel throughout the year and impact sea ice growth and nutrient exports to Arctic Ocean coastal waters. Continue reading “Glacial retreat affects river flows and aquifers”→
Coal power plants still to blame for emitting most of the toxic mercury pollution
Mercury continues to build up in Arctic ecosystems at levels that threaten the health and well-being of people, wildlife and waterways in the region.
A new study that looks at the sources of the toxic metal shows that airborne mercury is gathering in the Arctic tundra, where it gets deposited in the soil and ultimately runs off into waters. Scientists have long reported high levels of mercury pollution in the Arctic. The new research identifies gaseous mercury as its major source and sheds light on how the element gets there. Continue reading “Mercury pollution worsens in remote Arctic realms”→
Most agriculture in the southwestern U.S. is already marginal, possible only because U.S. taxpayers support cheap water for questionable crops. And because of global warming, the outlook is grim as the region continues to warm and dry.
By 2050, Arizona cotton production will drop to less than 10 percent of the crop yield under optimal irrigation conditions, a new MIT study projects. Similarly, maize grown in Utah, now only yielding 40 percent of the optimal expected yield, will decrease to 10 percent with further climate-driven water deficits. Continue reading “Global warming will devastate marginal farming areas”→
Farmers have known it for generations that heatwaves, drought and extreme rain are a bad recipe for growing wheat, and now scientists have quantified those impacts. Heat stress, combined with drought or excessive rain is responsible for about 40 percent of the changes in wheat yields from one year to another.
That’s bad news in a world that’s expecting extreme weather to intensify in the coming decades, but at least the stress index developed scientists with the European Joint Research Centre will help communities plan ahead and ameliorate at least some climate change impacts. Continue reading “Climate extremes have big effect on wheat yields”→
New research focuses on biophysical impacts of climate change
Vegetation plays a key role in the climate change equation, with a recent study showing that vegetation density has substantial climate impacts. According to the research by the European Union’s Joint Research Center, the findings show that vegetation has a warming effect in cold areas and cooling effect in warm areas.
Figuring out the net effect would help develop more integrated and effective climate mitigation and adaptation strategies. The puzzle is complex. Increasing greenhouse gases spur vegetation growth, but the overall effects at the global level are not clear. The new study explores how changes in leaf area (a measure of vegetation density) affect local climate. Continue reading “Increased greening amplifies global warming in boreal zones”→