Extreme heat and heat-wave events have already triggered major electricity shortages
like those seen in the summer of 2006. Heat map courtesy of NASA.
As the 21st century progresses, major cities in heavily air-conditioned California
can expect more frequent extreme-heat events caused by climate change according to
a report published in the June issue of the Journal of Applied Meteorology and Climatology.
This could mean increased demand for electricity which may increase the risk of power
shortages during heat waves, said Katharine Hayhoe, a climate researcher in the Department
of Geosciences who co-authored the report with researchers from the University of
If additional electricity were generated through fossil fuels, this could mean even
more emissions of heat-trapping gasses that cause climate change.
“Risk of electricity shortages can be reduced through energy conservation as well
as through reducing our emissions of heat-trapping gasses to limit the amount of
future climate change that can be expected,” Hayhoe said.
Before the end of the century, increases in extreme heat days could range from approximately
twice the present-day number for inland California cities such as Sacramento and
Fresno, to up to four times the number for previously temperate coastal cities such
as Los Angeles and San Diego.
Researchers used climate projections from three models to assess projected increases
in temperature extremes and day-to-day variability. Download the full report: Climate, Extreme Heat and Electricity Demand in California.
“Electricity demand from industrial and home space cooling already increases as a
near linear response to outdoor temperatures,” said Max Auffhammer, an assistant
professor of agriculture and resource economics at the University of California,
Berkeley. “With widespread increase in extreme heat days across the Western U.S.,
the electricity grid could be further strained and brownouts and rolling blackouts
may become more frequent.”
Temperature Records Already Broken
This year, California experienced an unusually early heat wave in May that set 119
new daily high temperature records. On May 19, Death Valley set a record for the
earliest day to reach 120 degrees, breaking the May 25, 1913, record. Now in its second heat wave this summer, record high temperatures have been broken
for several more California cities in recent days
This graph represents the dramatic temperature and emission increases projected for
“In the future, the state should brace for summers dominated by the heat-wave conditions,
such as those experienced this year,” said Norman Miller, lead author of the study
and a climate scientist at Lawrence Berkeley National Laboratory.
“Extreme heat and heat-wave events have already triggered major electricity shortages
like those seen in the summer of 2006. Given past events, the results of this study
suggest that future increases in peak electricity demand may challenge the current
and future electricity supply and transmission capacities.”
When the projected extreme heat and observed relationships between high temperature
and electricity demand for California are mapped onto current availability, the researchers
discovered a potential for electricity deficits as high as 17 percent during peak
electricity demand periods.
Similar increases in extreme-heat days are likely for other urban centers in Arizona
, New Mexico
, as well as for large cities in developing nations with rapidly increasing electricity
Hayhoe and Miller also contributed to the Nobel Prize-winning United Nations Intergovernmental
Panel on Climate Change.
Katharine Hayhoe photo courtesy Artie Limmer.