New research shows that more extreme climate conditions due to global warming are already affecting more than 250 national parks, including the Mojave National Preserve, Lake Mead National Recreation Area, the Chesapeake and Ohio Canal National Historical Park and Mammoth Cave National Park. Recent temperatures at Grand Canyon National Park have been at the extreme end of historical averages.
Coming on the heels of the Union of Concerned Scientists’ own recent report on climate impacts at some of the United States most iconic historic sites, a new study has shown that most U.S. National Parks are now experiencing warmer temperatures than at any time since the National Park Service was founded in 1916.
Climate changes in hundreds of national parks will require new approaches to resource management
National Park Service Scientists William Monahan and Nicholas Fisichelli analyzed the climate of the last 10-30 years for 289 national park units and compared it to the “historical range of variability” for the period 1901-2012. They found that “parks are overwhelmingly at the extreme warm end of historical temperature distributions.” 91% of the parks are warmer than they were, and this general pattern can be seen from the Pacific Islands to Alaska, to the U.S. East Coast.
Temperatures at the Grand Canyon are the high end of historic extremes. Photo: NPS
Published in the journal, PLOS ONE, the new research will likely have far-reaching consequences for how protected areas managers think about resource conservation and management in the future. Management strategies that have worked historically may no longer be effective in a rapidly changing climate.
For example, the authors make the case that because of sea level rise, managers at Point Reyes National Seashore in California may now need to include strategies to allow the shoreline and wetlands to migrate inland, rather than try to maintain historic conditions and protect and against sea level rise. Similar management choices will need to be made in many other parks. However, while the vast majority of the parks are getting warmer, there has been much more variability in precipitation trends, as would be expected based on observed trends and climate modeling projections. But the study authors identified some clear regional patterns. For example, parks in Hawaii and the desert southwest have become warmer and drier, whilst parks in the Northeast are now warmer and wetter.
Extreme climate conditions present a massive challenge in preserving park resources
Appomattox Court House National Historic Park in Virginia is one of the national parks that has witnessed a major warming trend. Photo: Jasperado
For resource management in parks it is important not only to understand long-term annual trends but also variability in inter-annual climate conditions. For example, while both Appomattox Court House National Historic Park in Virginia and Niobrara National Scenic River in Nebraska are in the extreme high temperature range compared to historical climate, the Appomattox site exhibits high variability in temperature between years, while Niobrara is in the low range for annual variability.
Seasonal variation can be important too. For example, the authors found that Assateague Island National Seashore (which is already under threat from sea level rise) in addition to experiencing extreme warm conditions in recent decades compared to its historic climate, has also suffered extreme wet conditions in the wettest quarter of the year and extreme dry conditions in the normally driest quarter of the year. Apostle Islands National Lakeshore in Wisconsin has already reached the hottest summer temperatures it has experienced in the last 100 years, and so any further warming will push it into new conditions which managers have never had to deal with since the creation of the park.
Joshua Tree National Park is one of many where scientists are detecting changes in climate and ecosystems. NPS photo by Robb Hannawacker
In response to the new study, National Park Service Director, Jon Jarvis, was quoted as saying “This report shows that climate change continues to be the most far-reaching and consequential challenge ever faced by our national parks.” To rise to this daunting challenge we must continue to fund cutting edge research to understand the impacts of climate change in our parks and protected areas, as well as urgently stepping up national efforts to reduce carbon pollution and prepare for the consequences of climate change.