CO ₂ and Temperature Effects on Evapotranspiration and Irrigated Agriculture

Global Change and Human Vulnerability to Vector-Borne Diseases

“…The Earth's surface is kept warm by a blanket of greenhouse gases, including water vapor, CO 2 (261), methane, nitrous oxide, and some industrial gases like chlorofluorocarbons. Each gas has different warming properties depending on its structure and persistence in the atmosphere.…”

“…However, the effects of higher concentrations of CO 2 on plants are to reduce their water loss through transpiration and to act as a fertilizer. The result is that plants produce more foliage with the same amount of water (261), provided that they do not exhaust the supply of other nutrients. Two consequences of this phenomenon that are relevant to the current consideration of the effects on vector-borne diseases are that the increased density of plant foliage will provide more favorable microclimates for insect vectors and that plant growth seasons will be extended in some situations, effectively increasing the duration of favorable microclimates each year.…”

“…Under good climatic and nutritional conditions, this will result in larger plants that provide more humid shelter for insect vectors and for plant pathogens. However, since plant growth under field conditions is often limited by factors other than water, such as nutrients, there is likely to be a generally higher water table and soil moisture content than occurs at present, unless global warming results in reduced rainfall or substantially increased evaporation (261). Such conditions are conducive to an increase in the frequency of pools of open water that provide suitable habitat for mosquito breeding.…”

Agro-Ecological Class Stability Decreases in Response to Climate Change Projections for the Pacific Northwest, USA

“…Our analyses do not consider potential beneficial effects of rising carbon dioxide (CO 2 ) levels on crop physiology including increases in water-use efficiency (WUE) and overall crop yield (Stöckle et al, 2010). Ramírez and Finnerty (1996) reported decreased potential evapotranspiration (PET) under elevated CO 2 conditions and a resultant increase in WUE. Therefore, HBIO, although a bio-temperature based estimate of PET, could decrease with greater levels of atmospheric CO 2 , potentially compensating for increased HBIO resulting from warming.…”

Increases in Growing Degree Days in the Alpine Desert of the San Luis Valley, Colorado

“…Increased temperatures are expected to exacerbate the need for irrigation as increases in crop evapotranspiration will occur (Adams 1989;Schimmelpfennig et al 1996;Fischer et al 1996;Ramirez and Finnerty 1996). Though Ramirez and Finnerty (1996) point out crop production will need additional water to reduce the impact of increased temperatures, they also indicate increased CO 2 concentrations may result in a greater income per hectare as crop production increases, even in light of increasing water needs.…”