JP

The Impact of Water Scarcity on Food, Bioenergy and Deforestation

Growing global food demand, climate change and climate policies favoring bioenergy production are expected to increase pressures on water resources around the world. Many analysts predict that water shortages will constrain the ability of farmers to expand irrigated cropland, which would be critical to ramping up production of both food and bioenergy crops. If true, bioenergy production and food consumption would decline amid rising food prices and pressures to convert forests to rain-fed farmland. Now a team of researchers at the MIT Joint Program on the Science and Policy of Global Change has put this prediction to the test.

To assess the likely impacts of future limited water resources on bioenergy production, food consumption and prices, land-use change and the global economy, the MIT researchers have conducted a study that explicitly represents irrigated land and water scarcity. Appearing in the Australian Journal of Agriculture and Resource Economics, the study is the first to include an estimation of how irrigation management and systems may respond to changes in water availability in a global economy-wide model that represents agriculture, energy and land-use change.

Next Steps in Tax Reform

The GOP tax reform, now adopted as the 2017 Tax Cuts and Jobs Act, aimed to cut business taxes to stimulate investment, lower some personal taxes, eliminate deductions and tax credits to help pay for the tax reductions, and reduce the shifting of profits abroad by U.S. companies. Some of these objectives have been achieved, but at the cost of a potentially substantial increase in the fiscal deficit, among other problems. As a result, corrections will be needed in future years.

Many of the Act’s undesirable features reflect its drafters’ inability to come up with sufficient revenue to compensate for the tax reductions. This paper explores a carbon dioxide (CO2) tax as perhaps the only measure that’s consistent with the declared tax-reform principles of the GOP leadership, likely to draw Democratic support, and large enough to compensate for the Act’s revenue-losing provisions. After summarizing the process that led to the Act and its major shortcomings, the researchers—applying the MIT U.S. Regional Energy Policy (USREP) model—show how, when the Act is opened up for repairs, a CO2 tax could help correct its flaws while serving environmental goals.

The greening of Northwest Indian subcontinent and reduction of dust abundance resulting from Indian summer monsoon revival

Due to an extremely dry climate and strong winds, the Northwest Indian Subcontinent (NWIS) undergoes heavy and frequent dust storms in the spring and summer. These dust storms can travel all the way from the NWIS (which encompasses southeastern Afghanistan, Pakistan and northwestern India) to North India and the Arabian Sea, blocking sunlight and degrading air quality in their path.

In their previous paper in Nature Climate Change, the co-authors found a positive trend of Indian summer monsoon (ISM) rainfall during the past 15 years—a revival of a major monsoon system that had declined for decades—and they analyzed its causes. In this paper, they show that the ISM revival is expanding rainfall distribution further northwestward, a development that could bring more rainfall to the NWIS. This increased rainfall could, in turn, boost vegetation growth and reduce the abundance of dust in the region.

Using satellite and other observations, the researchers demonstrate that the increasing monsoon rainfall is causing wetter soil and more vegetated areas in the Thar Desert and surrounding arid regions in the NWIS, resulting in lower levels of soil/mineral dust emissions in the area. Projected changes in vegetation growth and dust abundance in the NWIS has important implications for regional agricultural productivity and air quality.

Synthesis of the Southeast Atmosphere Studies: Investigating fundamental atmospheric chemistry questions

The Southeast Atmosphere Studies (SAS), which included the Southern Oxidant and Aerosol Study (SOAS); the Southeast Nexus (SENEX) study; and the Nitrogen, Oxidants, Mercury and Aerosols: Distributions, Sources and Sinks (NOMADSS) study, was deployed in the field from 1 June to 15 July 2013 in the central and eastern United States, and it overlapped with and was complemented by the Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. SAS investigated atmospheric chemistry and the associated air quality and climate-relevant particle properties. Coordinated measurements from six ground sites, four aircraft, tall towers, balloon-borne sondes, existing surface networks, and satellites provide in situ and remotely sensed data on trace-gas composition, aerosol physicochemical properties, and local and synoptic meteorology. Selected SAS findings indicate 1) dramatically reduced NOx concentrations have altered ozone production regimes; 2) indicators of “biogenic” secondary organic aerosol (SOA), once considered part of the natural background, were positively correlated with one or more indicators of anthropogenic pollution; and 3) liquid water dramatically impacted particle scattering while biogenic SOA did not. SAS findings suggest that atmosphere–biosphere interactions modulate ambient pollutant concentrations through complex mechanisms and feedbacks not yet adequately captured in atmospheric models. The SAS dataset, now publicly available, is a powerful constraint to develop predictive capability that enhances model representation of the response and subsequent impacts of changes in atmospheric composition to changes in emissions, chemistry, and meteorology.

© 2018 American Meteorological Society.

Pages

Subscribe to JP