Up In Smoke: Climate Change Burns the Planet

Warming Climate Plays Large Role in Western U.S. Wildfires, Scripps-led Study Shows

Research published in Science shows rising temperatures expected in the years ahead will exacerbate the number of large and costly fires A new study led by scientists at Scripps Institution of Oceanography at the University of California, San Diego, implicates rising seasonal temperatures and the earlier arrival of spring conditions in connection with a dramatic increase of large wildfires in the western United States.

In the most systematic analysis to date of recent changes in forest fire activity, Anthony Westerling, Hugo Hidalgo and Dan Cayan of Scripps Oceanography, along with Tom Swetnam of the University of Arizona, compiled a database of recent large western wildfires since 1970 and compared it with climate and land-surface data from the region. The results show that large wildfire activity increased "suddenly and dramatically" in the 1980s with longer wildfire seasons and an increased number and more potent wildfires.

The scientists compiled a comprehensive time series of 1,166 forest wildfires of at least 1,000 acres that had occurred between 1970 and 2003 from wildfire data covering western U.S. Forest Service and National Park Service lands. To investigate what role climate might play, the researchers compared the time series, the timing of snowmelt and spring and summer temperatures for the same 34 years.

For the timing of peak snowmelt in the mountains for each year, they used the streamflow gauge records from 240 stations throughout western North America. The team also used other climatic data such as moisture deficit, an indicator of dryness.

The results point to a marked increase in large wildfires in western U.S. forests beginning around 1987, when the region shifted from predominantly infrequent large wildfires of short duration (average of one week) to more frequent and longer-burning wildfires (five weeks). The authors found a jump of four times the average number of wildfires beginning in the mid-1980s compared with the 1970s and early 1980s. The comparison showed that the total area burned was six and a half times greater. Also in the mid-1980s, the length of the yearly wildfire season (March through August) extended by 78 days, a 64 percent rise when comparing 1970-1986 with 1987-2003.

The aftermath of the Aspen Fire, a large and severe forest fire that occurred in the summer of 2003 in the Santa Catalina Mountains near Tucson, Ariz.

The researchers determined that year-to-year changes in wildfire frequency appear "to be strongly linked to annual spring and summer" temperatures with "many more wildfires burning in hotter years than in cooler years."

They established a strong association between early arrivals of the spring snowmelt in the mountainous regions and the incidence of large forest fires. An earlier snowmelt, they said, can lead to an earlier and longer dry season, which provides greater opportunities for large fires. Overall, 56 percent of the wildfires and 72 percent of the total area burned occurred in early snowmelt years. By contrast, years when snowmelt happened much later than average had only 11 percent of the wildfires and 4 percent of the total area burned.

"At higher elevations what really drives the fire season is the temperature. When you have a warm spring and early summer, you get earlier snowmelt," said Westerling. "With the snowmelt coming out a month earlier, areas then get drier earlier overall and there is a longer season in which a fire can be started—there's more opportunity for ignition."

The greatest wildfire increases occurred in the Northern Rockies, where forest ecosystems in middle elevations were found to be highly susceptible to temperature increases. Other significant wildfire increases were found in the Sierra Nevada, the southern Cascades and the Coast Ranges of northern California and southern Oregon.

"I see this as one of the first big indicators of climate change impacts in the continental United States," said research team member Thomas Swetnam, director of the Laboratory of Tree-Ring Research at The University of Arizona in Tucson. "We're showing warming and earlier springs tying in with large forest fire frequencies. Lots of people think climate change and the ecological responses are 50 to 100 years away. But it's not 50 to 100 years away—it's happening now in forest ecosystems through fire."

The authors state that climate model projections, driven by potential increases in atmospheric greenhouse gas concentrations, indicate that warmer springs and summers will likely continue and intensify in the coming decades, accentuating conditions favorable to large wildfires.
Westerling says that the paper's results indicate that measures to limit future climate change could help to curtail catastrophic increases in future summer wildfires. If climate warms markedly over today's levels, intensified fuels management and fire suppression are not likely to be effective in much of the western U.S., he said.

"The overall importance of climate in wildfire activity underscores the urgency of ecological restoration and fuels management to reduce wildfire hazards to human communities and to mitigate ecological impacts of climate change, especially in forests that have undergone substantial alterations due to past land uses," the authors note in the paper.

The authors conclude that the increased frequency of large and devastating wildfires may significantly change forest composition and reduce tree densities, transforming the western U.S. forests' role as a storage "sink" for sequestering some 20 to 40 percent of all U.S. carbon to a source for increasing carbon dioxide in the atmosphere.

The research was supported by the National Oceanic and Atmospheric Administration's Office of Global Programs, the National Fire Plan via the United States Forest Service's Southern Research Station and the California Energy Commission.

Note: Anthony Westerling was recently appointed to the faculty of the University of California, Merced, and conducted the research while at Scripps.

Windpower continues along its exponential growth curve.

Wind is the world’s fastest-growing energy source with an average annual growth rate of 29 per cent over the last ten years. In contrast, over the same time period, coal use has grown by 2.5 per cent per year, nuclear power by 1.8 per cent, natural gas by 2.5 per cent, and oil by 1.7 per cent (See Table).


Europe continues to lead the world in total installed capacity with over 40,500 megawatts, or two-thirds of the global total (See Figure and Table). These wind installations supply nearly 3 per cent of Europe’s electricity and produce enough power to meet the needs of over 40 million people. The European Wind Energy Association (EWEA) has set a target to satisfy 23 per cent of European electricity needs with wind by 2030. EWEA also notes that Europe has enough wind resources to meet the electricity demands of all of its countries.

Germany, the country with the most installed wind-generating capacity, now gets 6 per cent of its electricity from its 18,400 megawatts of wind power. Spain, in second place with over 10,000 megawatts of capacity, gets 8 per cent of its electricity from wind.



Wind Park, Jutland, Denmark
© Jorgen Schytte/Still Pictures
Denmark’s 3,100 megawatts of wind capacity meet 20 per cent of its electricity needs, the largest share in any country. It ranks fifth in the world in installed capacity. Denmark is also the global leader in offshore wind power installations, with 400 megawatts of existing capacity. Globally, over 900 megawatts of offshore wind capacity will be installed by the end of 2006, all in Europe.


The United States has installed 9,100 megawatts of wind power capacity. The US wind industry installed a record-breaking 2,400 megawatts of wind power in 2005, up from installing just 370 megawatts in 2004 and 1,700 megawatts in 2003 (See Figure and Table). This inconsistent growth is mostly due to the intermittent availability of the federal wind production tax credit (PTC) that currently stands at 1.9 cents per kilowatt hour. In mid-2005, Congress extended the PTC by two years, marking the first time lawmakers extended the tax credit without first allowing it to lapse. With the PTC guaranteed for the year, the US wind industry projects that it will install 25 per cent more capacity in 2006 than it did in 2005.


Canada’s installed wind capacity of 680 megawatts at the end of 2005 is expected to increase to 1,200 megawatts by the end of 2006. While Canada’s federal government targets the installation of 4,000 megawatts of wind energy by 2010, its more ambitious provincial governments plan to install a combined 9,200 megawatts by 2015.


Asian countries have installed nearly 7,000 megawatts of wind-generated electricity capacity. India has 4,400 megawatts of capacity, ranking fourth after Germany, the United States, and Spain. Wind power in China, currently at 1,260 megawatts, is beginning to flourish due to the country’s new Renewable Energy Law. This law provides tax incentives and subsidies for wind power and targets the development of 30,000 megawatts of wind capacity by 2010. Ambitious as these goals are, experts within the Chinese wind industry report that China could produce 400,000 megawatts of wind capacity by 2050. For comparison, China’s total electric power generation capacity at the end of 2003 was 356,100 megawatts.


While three-quarters of all wind power has been installed in only five countries, the wind power installed in the rest of the world has grown by an average of 35 per cent per year over the past ten years. Australia’s wind capacity almost doubled in 2005 to 710 megawatts. It leads the countries of the Pacific region, which, as a whole, have developed 890 megawatts. Latin America and the Caribbean have installed 210 megawatts of capacity. North African countries are also beginning to develop wind power and have installed 310 megawatts. Egypt and Morocco have installed 150 and 60 megawatts of wind capacity, respectively.

Overall, the cost of wind power has decreased by nearly 90 per cent since the 1980s to 4 US cents or less per kilowatt-hour in prime wind sites (See Figure). In some markets wind-generated electricity is cheaper than electricity from conventional energy sources. The cost of wind power has fallen due to advances in technology, declines in the costs of financing wind projects, and the economies of scale of turbine and component manufacturing and construction.



Blyth, the UK's first offshore windfarm.
© AMEC Border Wind
The explosive growth of world wind power is due in large part to its increasing technological sophistication. Modern turbines are taller and have longer rotor blades than the turbines of 20 years ago, allowing them to produce up to 200 times more power. Since the “fuel” for wind power is free and unlimited, 75 to 90 per cent of the costs of generating electricity with wind lie in manufacturing and constructing wind turbines and connecting them to the grid. Once turbines are installed, the remaining costs are primarily turbine operation and maintenance, land-use royalties, and property taxes.


In the United States and around the world, energy markets are heavily regulated. Some 48 countries have regulations or laws in place that favour the growth of renewable energies. Examples of these include renewable portfolio standards that set a minimum for renewable energy purchases and tax incentives such as the United States’ PTC. However, decades of political and financial support to fossil fuel industries often undermine the competitiveness of wind energy.


If environmental, social, and human-health costs were reflected in the economics of electricity generation, wind energy would become even less costly compared to energy derived from fossil fuels. Unlike conventional power plants, wind electrical generation does not release greenhouse gases that warm the climate or other polluting emissions.


Wind power provides more benefits than just affordable clean energy. The prices of wind-generated electricity are stable and not subject to the price volatility of fossil fuels. Wind power supports local economic development since the jobs, royalties, and tax revenues from wind-generated electricity production tend to stay in the community. And since wind is inexhaustible it offers long-term energy security that electricity derived from nonrenewable fossil fuels cannot.