US Drought Monitor
Each color on this map represents a different intensity
of drought conditions. Scientists determined regional intensities
by first combining several drought indicesnumbers that
combine data on precipitation levels, soil moisture, stream
flows, vegetation health, and moreand then making adjustments
based on local moisture reports.
Many future-climate models predict that increasing global
temperatures may lower precipitation in low- and mid-latitudes.
Longer, more severe droughts may be part of the climate-change
picture. To explore this possibility, experts are watching
for changes in drought patterns around the globe.
Evaluating data over time may reveal long-term drought trends,
allowing scientists to understand possible connections between
drought and climate change. But such connections come with
a measure of uncertainty: Topographical factors (such as mountains,
coastlines, lakes, and soil types) play an important role
in regional climatesso drought patterns in New England,
for example, may be very different from drought patterns elsewhere.
Many climate models do not consider these topographical factors,
so its difficult to predict how global climate change
may affect drought trends.