By the end of the century, climate change could drive typical temperatures in Yosemite, Sequoia, Kings Canyon, Death Valley and other national parks in California more than 7 degrees hotter than they were in the later half of the 20th century, according to a new study.

The 34-page report from the Rocky Mountain Climate Organization and the Natural Resources Defense Council, which earlier this year released similar studies on how climate change could impact Glacier National Park and Shenandoah National Park, warns of not only biological change driven by these higher temperatures, but also of economic fallout.

“The natural and cultural resources of California’s national parks are directly linked to over one billion dollars in economic activity and 19,000 jobs," said Theo Spencer, a senior advocate in NRDC's Climate Center. "By acting now to reduce the pollution that causes global warming we will preserve these jobs and create new ones while continuing America's long-standing position of technological leadership.”

Part of the hit on California's economy could be waning tourism to these park icons. While hotter temperatures might initially see more people head into the High Sierra parks of Yosemite, Sequoia, and Kings Canyon, or to coastal parks such as Point Reyes National Seashore and Redwood National Park, "... as temperatures get too hot, outdoor recreation even in the mountains becomes less pleasant, and people may find other ways to get a break from the heat," the report notes.

With what the California Climate Change Center calls “medium-high” future emissions of heat-trapping gases, the average of six climate models is for Yosemite to get 7.5°F hotter by 2070-2099 than it was in 1961-1990, according to the study released Tuesday. "That would be enough to make the national park 0.3° hotter than Sacramento historically has been," the report noted.

Average results from other, park-specific projections include that Sequoia and Kings Canyon national parks could get 7.6° hotter, making them 0.6° hotter than the Sonoma County coast has been. Point Reyes National Seashore could get 6.0° hotter, making it as hot as Santa Barbara has been. Death Valley National Park, already the hottest place in North America, could get 8.1° hotter. Average temperatures in Joshua Tree National Park could go up 7.4° and in Mojave National Preserve by 8.0° hotter, making each hotter than Death Valley’s historic average temperature.

The report cites a range of impacts to the ten national parks in California:

* Joshua trees, which need freezing temperatures to set seeds, are projected to disappear entirely from the national park named after them, and from most of Death Valley National Park and Mojave National Preserve.

* In Redwood National Park and Muir Woods National Monument, higher temperatures already have reduced by 30 percent the coastal fog that redwoods depend on for nearly half their water supply. A continued decrease in the fog could keep the coast redwoods from growing to the astonishing heights that make them the world’s tallest trees.

* In Sequoia, Kings Canyon, and Yosemite, giant sequoias may not be resilient to the water stress and increased wildfire expected with rapid climate change, according to National Park Service and U.S. Geological Survey scientists.

* Yosemite Falls, mostly fed by snowmelt, could dry up more often and earlier in summers, depriving many park visitors of one of the world’s greatest sights.

* As Yosemite, Sequoia, and Kings Canyon have gotten hotter and drier, pine and fir trees are dying more quickly. The death rate of trees has nearly doubled over just the past two decades.

* Sea-level rise of 2.0 to 4.7 feet in this century, as projected by the California Climate Change Center, would lead to flooding by storm surges and the permanent inundation of low-lying areas in Point Reyes National Seashore, Golden Gate National Recreation Area, and Redwood National Park. At risk are beaches, wetlands, other wildlife habitat, historic structures, highways and roads, campgrounds, picnic areas, and a visitor center.

* In Yosemite, mammals already are moving upslope to stay ahead of rising temperatures. About half of small mammal species in Yosemite now live at elevations different from where they were found nearly a century ago. Most have moved to higher elevations, by an average of about 500 yards higher. Along the coast, seals and shorebirds could lose habitat to a higher sea, and many may abandon the coastal national parks as suitable areas disappear.

“We need to reduce heat-trapping pollution to keep these national parks the special places that Americans know and love," said Stephen Saunders, president of the Rocky Mountain Climate Organization and a former deputy assistant secretary of the Interior who was the lead author for the report. "If we keep changing the climate the way we are, it will hurt tourism and the state’s economy. In California, climate disruption is a jobs-killer.”

In arriving at their conclusions, the report's authors examined two sets of future emissions – "the medium-high scenario and one with lower (but still fairly high) emissions. With lower emissions, Yosemite would get 4.5° hotter rather than 7.5° hotter – still enough for widespread, severe impacts."

“To really protect these special places, we need to get serious about sharply cutting heat-trapping pollution, and doing it now,” said Mr. Saunders, who noted that heat-trapping gases have long-lasting effects in the atmosphere, and emission reductions made sooner will have greater effect than those made later. The good news is that the actions that protect the climate also save energy costs and create clean-energy jobs."

According to the report, progress to stave off these higher temperatures is being made by the state of California.

The state of California is beginning to do its share by taking far-reaching actions under its 2006 landmark climate-protection law, the Global Warming Solutions Act (still more widely known by its legislative title, Assembly Bill 32). Actions under this state law not only will reduce climate change but also, studies consistently show, actually strengthen the state's economy by reducing energy costs and creating clean-energy jobs.

At the same time, the federal government needs to do more to combat climate change, the report said.

Among the steps the report's authors believe the government should take are:

* Enacting comprehensive mandatory limits on global warming pollution to reduce emissions by at least 20 percent below current levels by 2020 and 80 percent by 2050. This will deliver the reductions that scientists currently believe are the minimum necessary, and provide businesses the economic certainty needed to make capital investments to achieve those reductions.

* Protecting the current Clean Air Act authority of the U.S. Environmental Protection Agency (EPA). This includes current authority under the Clean Air Act to set standards to curb global warming pollution from vehicles, power plants, and large industrial sources. The Supreme Court held in its landmark 2007 decision that EPA must act if it finds, based on the science, that carbon dioxide and other global warming pollutants endanger public health and the environment.

Accordingly, EPA issued consensus national standards on April 1 to cut global warming pollution from new vehicles. And on May 13, EPA issued a rule requiring that the biggest new and expanded pollution sources start applying available and affordable pollution control measures starting in 2011.

EPA authority must also be maintained to institute the tightest pollution controls necessary to protect public health and the environment. That includes standards for the pollution that causes smog and other dangerous and fatal respiratory ailments, pollution of hazardous materials like mercury and dioxin, and dangerous waste from power plants and other industrial facilities.

* Overcoming barriers to investment in energy efficiency to lower emission-reduction costs, starting now. To fully harness energy efficiency potential, many opportunities require additional federal, state, or local policies to unleash investments that are already cost-effective even without a price on greenhouse gas emissions. Policies include building, industry, and appliance efficiency (standard) upgrades, as well as incentives for “smart” transportation and growth and for advanced vehicles.

* Accelerating the development and deployment of emerging clean-energy technologies to lower long-term emission reduction costs. That means incentives and investments in renewable electricity, low-carbon fuels, and carbon capture and storage; a federal renewable-energy standard; and infrastructure upgrades to support transmission capacity for these renewable assets. Finally, regulations are needed to require any new coal-fired power plant to capture and permanently geologically sequester at least 85 percent of its carbon dioxide emissions, along with state and federal regulatory frameworks for site selection, operation, and monitoring for carbon capture and geologic storage systems.

You can find the entire report at this site.