Global Climate Change

The global climate is changing, and is already affecting the Greater Yellowstone Ecosystem. Scientists predict wolverine, lynx, and pikas (shown here) may lose habitat in the park.

NPS / Janine Waller

 

Today, climate change is no longer a vague threat in our future; it is the changing reality we live with, and requires continuous planning and adaptation. Climate change presents significant risks to our nation’s natural and cultural resources. Though natural evolution and change are an integral part of our national parks, their physical infrastructure, natural and cultural resources, visitor experience, and intrinsic values are at risk from the effects of climate change. Climate change is fundamentally transforming protected lands and will continue to do so for many years to come. Climate change will affect everyone’s experience of our national parks.

 

Atmospheric concentrations of CO2 began a marked increase that coincides with the Industrial Revolution of the late 1800s. CO2 levels rose by more than 20% in the 50-year period 1958–2008.

CO2 Program of the Scripps Institute of Oceanography, scrippsco2.ucsd.edu

Some effects are already measurable. Warmer temperatures are accelerating the melting of mountain glaciers, reducing snowpack, and changing the timing, temperature, and amount of streamflow. These changes are expected to result in the loss or relocation of native species, altered vegetation patterns, and reduced water availability in some regions. Wildfire seasons have expanded, and fires have increased in severity, frequency, and size. More acres burned in the fire season of 2016 than in any year in the last century, except for 1988. Conditions that favor outbreaks of pests, pathogens, disease, and nonnative species invasion occur more frequently than in the recent past. In Alaska, melting sea ice threatens marine mammals as well as coastal communities, while thawing permafrost disrupts the structural basis of large regions, jeopardizing the physical stability of natural systems as well as buildings, roads, and facilities. Rising sea levels, ocean warming, and acidification affect wildlife habitat, cultural and historic features, coastal archeological sites, and park infrastructure, resulting in damage to and the loss of some coastal resources. Some studies suggest that extreme weather events such as thunderstorms, hurricanes, and windstorms that damage park infrastructure and habitat are increasing in frequency and intensity. Climate change will manifest itself not only as changes in average conditions, creating a “new normal,” but also as changes in particular climate events (e.g., more intense storms, floods, or drought). These extreme climate events may cause widespread and fundamental shifts in conditions of park resources.

A 2014 assessment of the magnitude and direction of ongoing climate changes in Yellowstone National Park showed that recent climatic conditions are already shifting beyond the historical range of variability. Ongoing and future climate change will likely affect all aspects of park management, including natural and cultural resource protection as well as park operations and visitor experience. In order to deal with the predicted impacts, effective planning and management must be grounded in concrete information about past dynamics, present conditions, and projected future change.

 

Words to Know

Albedo: the fraction of solar energy (shortwave radiation) reflected from the Earth back into space. It is a measure of the reflectivity of the earth’s surface. Ice, especially with snow on top of it, has a high albedo: most sunlight hitting the surface bounces back towards space.

Climate: long-term meteorological conditions that prevail in a region, with a decade as the minimum span of averages.

Gridded climate data: In order to consistently compare historic climate trends from one area to another, scientists estimate weather data in places and during time periods not covered by weather stations using computer models. The models use a combination of existing and corrected weather records, temperature change based on elevation, knowledge of local climate anomalies, and satellite data to estimate temperature and precipitation values. Daily or monthly weather values are calculated for every square in a regular grid pattern and analyzed to define the climate over time. The three most commonly used data sets are PRISM, DAYMET, and TopoWx. As useful as these data sets are, it is important to remember that they are approximations or best estimates. Ultimately, they are confirmed only when different people, using different data types and analysis techniques, reach the same conclusions.

Phenology: relationship between periodic biological changes —like the budding of trees or arrival of migratory birds in the spring—and seasonal changes such as temperature.

Snow-water equivalent: the amount of water in the snow, usually expressed as inches. If you melted all the snow from one location the depth of the resulting water, is the snow water equivalent (SWE). When comparing the amount of snow at different locations, it is easier to think in terms of SWE rather than snow depth, because there are no complications from snow being fluffy in one place and dense and compacted somewhere else.

Weather “Normals”: 30-year averages of temperature or precipitation. If a daily or monthly measurement is said to be “above normal” it means, by convention, the measurement exceeds the most recent set of 30-year averages. Every 10 years, the time period used to calculate the official “normal” values is calculated and updated by the agencies that run the weather stations (e.g., NOAA, NRCS). Continuously updating the reference period to the most recent 30 years made sense when climate data were used primarily for short-term forecasting and agricultural applications because the goal was to compare the current year to what most people had experienced recently and were “used to.” In contrast, in the era of anthropogenic climate change, it often makes sense to choose an older, historic reference period. Because of this, scientists sometimes choose a different reference period than the current “normal” when they compare conditions from the past to current conditions. It is important to be aware of this subtle, but important, difference in reference conditions.

Weather: the state of the atmosphere at a given time and place, and for the next few days to a month.

 

A. Observed global mean combined land and ocean surface temperature anomalies, 1850-2012. Top: annual mean values. Bottom: decadal mean values including the estimate of uncertainty for black dataset. B. Map of the observed surface temperature change from 1901-2012. See Resources & Issues for more.

From http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_SPM_FINAL.pdf Summary for Policy makers, IPCC report 5th, 2013

Climate Science History

• 1700s: The Industrial Revolution is underway; manufacturing begins producing greenhouse gases such as carbon dioxide and methane.
• 1827: Jean-Baptiste Joseph Fourier describes what is later termed, the “greenhouse effect.”
• 1896: Savre Arrehnius calculates that increasing atmospheric greenhouse gases will cause global warming.
• 1958: Charles David Keeling begins measuring atmospheric carbon dioxide from Mauna Loa, Hawaii. • 1963: Keeling warns of 10.8°F temperature rise in next century.
• 1965: First Global Climate Models (GCM) developed.
• 1969: Weather satellites begin providing atmospheric data.
• 1978: Satellites begin measuring sea ice in both the Arctic and Antarctic.
• 1988: The Intergovernmental Panel on Climate Change (IPCC) is established.
• 1997: The Kyoto Protocol sets targets for greenhouse gas emissions for most industrialized nations (US does not sign).
• 2007: IPCC begins its 4th report, “Warming of the climate system is unequivocal.”
• 2009: President Obama Announces National Fuel Efficiency Policy for Cars and Trucks (http://www.whitehouse.gov/the-press-office/president-obama-announces-national-fuel-efficiency-policy)
• 2009: Secretary Salazar signed Secretarial Order 3289 which mandates a department-wide strategy to address climate change. This order also established 8 Climate Science Centers, to conduct high-level climate science. DOI established 21 Landscape Conservation Cooperatives where climate science is being applied for resource management.
• 2009: Copenhagen Summit held; an accord reached for nonbinding actions to address climate change.
• 2009: The EPA Administrator, Lisa Jackson, signed an Endangerment Findings for greenhouse gases which says the current and projected concentrations of the six key well-mixed greenhouse gases — carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6) — in the atmosphere threaten the public health and welfare of current and future generations (See: http://www.epa.gov/climatechange/endangerment/).
• 2010: The NPS releases:

−− The Climate Change Response Strategy: science, adaptation, mitigation, and communication.

−− The Green Parks Plan to help guide parks in sustainable operation.

−− The Climate Change Action Plan 2012–2014 describes prioritized actions.

• 2012: Yellowstone Center for Resources creates a Physical and Climate Resources branch.
• 2013: IPCC releases 5th report, detailing the current state of scientific knowledge about global warming trends.

 

Frequently Asked Questions

Why do you say climate change now, instead of global warming?

Though the overall global temperature is increasing, the term “climate change” includes more of the actual impacts that we see as a result of this increase. Changing amounts of greenhouse gases in the atmosphere also lead to severe storms, drought, sea level rise, insect infestations, and other consequences that can be different anywhere on earth.

What is causing climate change?

Changes in climate are due primarily to human-caused emission of heat-trapping gases such as carbon dioxide (CO2). These greenhouse gases have been on the rise since the 1800s, and their effect on climate will persist for many more decades. Levels of carbon dioxide and methane (another greenhouse gas) in the atmosphere are higher now than in the last 650,000 years. As humans continue burning more and more fossil fuels, scientists believe the impacts of global warming will accelerate.

Has global climate warmed before?

Yes, but never this much, and never this fast. Prehistoric fossil records show us that Earth’s climate is warming 40 times faster than any other period in the planet’s history.

Can you tell about climate from changes in the weather?

Weather is the temperature and precipitation patterns that occur over days or weeks. Climate is a trend in weather conditions over decades or centuries. While weather does play a part in our experience of climate, it is just one small corner of a much bigger picture.