The Climate will Change-Virginia will have water

Equilibrium climate sensitivity (ECS) is the global warming that would occur if the atmospheric carbon dioxide (CO2) concentration were instantly doubled and the climate were then brought to equilibrium with that new level of CO2. The actual warming that would occur remains one of the most important unknowns in climate change science. The current concentration of CO2 can be measured and the likely future concentrations of CO2 have been modeled, but the actual response of the planet to CO2 concentrations in the atmosphere has remained uncertain.

The ‘likely’ range of ECS assumed by the Intergovernmental Panel on Climate Change (IPCC) has remained at 1.5–4.5 degrees Celsius for more than 25 years. Last month a group of scientists at Exerter University and the U.K.’s Center for Ecology and hydrology lead by Peter Cox published a paper where, using a new methodology, they have narrowed the probable temperature range: 2.2 Celsius to 3.4C, with a best estimate of 2.8C with 66 % confidence limits (equivalent to the IPCC ‘likely’ range. Good news for mankind.

The scientists used what they describe as an ensemble of climate models to define an emergent relationship between CO2 concentration and temperature. Possibility not taken into consideration by their new model is the possibility of rapid shifts in climate brought on by the planet itself. As Dr. Cox points out in a press release there is evidence in history that the planet climate system can undergo abrupt changes. Even with this good news, the plant is going to respond to the current and projected future CO2 concentrations.

The United States and other governments have worked to document the CO2 in the atmosphere, temperatures and climate patterns. Unfortunately, the uncertainty surrounding climate sensitivity to CO2 remains and how climate change will impact water availability. Unlike climate change water problems are shorter term. Without water we die, not in 2100, but in under a week. When water supplies are short as in Cape Town, South Africa, people work to find solutions; reduce water use, change behavior, find new sources of water- find solutions in real time. Nonetheless, water problems are very difficult to solve once they become a crisis.

The more than 6 million residents of the Washington, D.C., metropolitan area rely on the Potomac River to supply approximately three-quarters of its water the rest comes from groundwater sources and the Occoquan River, a tributary of the Potomac River formed by the confluence of Broad Run and Cedar Run and joining with Bull Run before it meets the Potomac.

Regionally, there is a cooperative system of water supply management for the Potomac and Occoquan to share the water among the diverse users, all depending on the Potomac River, its tributaries, and associated land and groundwater resources. Sustainable management of the water resources across the multi-jurisdictional basin requires bridging social, political, and environmental differences. This can only be achieved through regional cooperation and encouragement of comprehensive planning to include providing adequate, quality and sustainable surface water and groundwater –together source water for public and private water supplies.

The Virginia Legislature has just passed SB 211ER- Comprehensive plans; groundwater and surface water. This law authorizes a locality to include in their comprehensive plan their long-range recommendations for groundwater and surface water availability, quality, and sustainability. The bill requires the local planning commission to survey and study groundwater and surface water availability, quality, and sustainability in the preparation of a comprehensive plan. In other words, Virginia will plan to provide adequate water for all.

Cox, Peter M., Huntingford, Chris, Williamson, Mark S.; “Emergent constraint on equilibrium climate sensitivity from global temperature variability” Journal Nature, 2018/01/17/ Volume 553.