Climate changes and the local environment:
Mohave County is located in Northwestern Arizona, and includes part of the Grand Canyon National Park, as well as several federally recognized Native American Reservations. Its annual average temperatures have risen by an average of 0.2°F per decade between 1895 and 2016. However, this average hides the fact that average temperatures in the county and the state were mostly stable until roughly 1975. After that year, the trend in average temperatures began rising very quickly, and this caused a worrying increase in the frequency and intensity of wildfires and droughts.
These weather and climate-related events have had devastating effects in the local environment. As much as 15 per cent of Arizona is covered by national forests, and the hotter and drier conditions have made it easier for wildfires to occur. According to U.S. Forest Service records, large wildfires (of more than 1,000 acres) in the state have increased from approximately 5 per year before 1980, to a current average of near 20.
Drought has affected the Colorado river, a source of water for over 30 million people, including a large share of Mohave County and the State of Arizona. For example, the Upper Colorado Basin has seen more common and severe droughts in the last 50 to 90 years. In the period between 2000 and 2014, the river’s flow declined by 19 per cent compared to the average between 1906 and 1999. Researchers have estimated that warmer temperatures account for up to one-sixth of these losses, which are approximately equal to enough water to support 1 million households for a year.
How we know:
These climate and weather reconstructions are based on several tools made available online by several United States agencies, such as the National Oceanic and Atmospheric Administration (NOAA)’s State Annual and Seasonal Time Series. This site is useful to see the evolution of temperatures at the state level since 1895, and its information is obtained from the U.S. Climate Divisional Dataset, used often for agricultural matters. NOAA’s Climate at a Glance tool is intended for studying the changes and variability of climate, and has adjusted the data to take into account artificial effects that affect climate, such as urbanization.
Another important resource is the United States Drought Monitor, which develops weekly maps of drought conditions across the country, and uses climate, soil, and water data, together with reports from 350 experts across the country. The U.S. Climate Resilience Toolkit helps people become informed about their risks and opportunities related to the changing climate, and to help them become more resilient. One of its tools is the Climate Explorer, which allows users to explore the potential damaging effects of climate on the population and their valued possessions, such as land and crops. To do this, it shows projections of temperatures, precipitation, and others for two possible futures: one in which humans make a moderate attempt to reduce their carbon emissions, and another in which humans continue to act as usual.
Some of the biggest effects of climate change in Arizona have been linked to health concerns, disruptions in the water supply for farms and cities, and the destruction of the environment with wildfires. In the summer of 2017, the state made nationwide news when numerous flights were cancelled in Phoenix due the excessive heat. These extreme temperatures caused near 1,300 deaths between 2005 and 2015, and the number of heat-related illnesses has been increasing, according to a medical director at the Banner University Medical Center in Phoenix. The Environmental Protection Agency (EPA) has reported that more than 2 per cent of the land in Arizona has burned per decade since 1984, and the smoke produced often damages the quality of the air and water, and creates health problems for the population.
In Mohave County, the most significant human consequences of climate change can be found in the water supply disruption to households, and in the Native American communities. Decreasing water reserves in important bodies of water like Lake Mead, and the increasing water needs due to growing cities and new farms that move from California’s even more extreme water shortage, have led to severe concerns and restrictions on water use. Native American tribes have seen their traditional practices challenged, as they are typically very dependent on agriculture and the raising of livestock, which in turn depend on weather and the availability of water. For the Mohave tribe, a drier Colorado River means a disruption to their traditions, as they believe that the river was created by their ancient deity Mastamho as part of their sacred landscape. Despite this worrisome picture, in a Climate Central report, Arizona’s government received a failing grade for its average level of wildfire preparedness, and a near-failing grade for its drought preparedness, as its plans do not account for the devastating effects of climate change.
The Future is Drying Up. NY Times Magazine
Where the River Runs Dry. The New Yorker
The $2.4 Billion Plan to Water California by Draining the Mojave. Wired
Wildfires, Once Confined to a Season, Burn Earlier and Longer. NY Times
Article author: Alejandro Carrera Rodriguez, Georgetown University
Article editor: Dr. Dagomar Degroot, Georgetown University