Green Horizon: global warming and water

global warming and water

Posted by Greg Gerritt on 02/04/07

I recently testified in front of the RI joint Senate committee looking at Water issues in RI. The committee is mostly receiving testimony on the current state of affairs, so I tried to provide a bit of the long term context for them, noting how global warming, and the things causing it and what we might do to mitigate it, could effect the water supply in Rhode Island.

I especially focused on the fact that even if total rainfall in RI is barely effected we might still see longer drought periods, and that this might intersect with several long term trends in the global food supply, both in terms of harm to agriculture from global warming and that as we try to reduce greenhouse gas emissions we shall be shipping less food cross country. The end result is that RI will need to grow more food, but at a time when water supplies for irrigation are even more stressed.

Most of the committee members were receptive to this message, but at least one committee member said he was not interested in this topic, he was only focusing on pipes. I did not reply directly to him, but what I should have said was that since water infrastructure will be built over the next twenty or thirty years and is going to last 100 years, then you have an obligation to all of us in Rhode island to think about what will happen as what you are discussing will be still in use when the climate is radically altered, and both the effects of global warming and how we react to it need to be in your calculations. Given the recent reports, I trust those on Smith Hill will get that message, and not only in deliberations about water.

Comments

Thanks Greg. The forecast here for the impact of global warming that will decrease the snow pack which makes a significant contribution to the Rio Grande stream flow. There is an ongoing effort to merge the science and the policy which is beneficial. http://www.nmclimatechange.us/ A critical element that is missing is that New Mexico by itself is not a significant contributor of greenhouse gases. As a result even on our worst days our efforts as one state will not significantly contribute to the atmospheric restoration required to stablize or reduce global temperature rise.

As in water planning there remains an effort to evade the issue of growth and its impact on emissions and energy production in the state. Efforts are by some to continue to increase urban growth and economic development and some still see energy production as a panacea for the state to supply to others in the West.

Drought is recognized but little is proposed to mitigate for the consequences of it. We have already had small towns ship in potable water via tanker trucks as supply was reduced to the point of not being able to supply the amount needed for the small rural population in this region. Urban areas remain dependent on groundwater supplies of water with no clear indication of how long they can sustain themselves before it becomes economically or geologically unfeasible.
The Water Assembly http://www.waterassembly.org has included demands to increase both the supply and decrease the demand of the water resources. It has also proposed that land use and water use be integrated. These are the political issues of our times and when we put them on the table we will see more clearly how things break down in a bioregionally, sustainable agenda.

By Martin Zehr on 2007 02 04

Water planning has struggled with incorporating variability of supply. As pointed out in the OSE's report on the impacts of climate change, we also need to consider changes in our water management.

The Impact Of Climate Change On New Mexico’s Water Supply And Ability To Manage Water Resources
Office of the State Engineer/Interstate Stream Commission (July 2006)

The impacts to the State are anticipated to be significant for water managers and users, with changes to both supply and demand including:

§ temperatures have already risen in New Mexico and are predicted to continue to increase;
§ changes in snowpack elevations and water equivalency;
§ changes in available water volumes and in the timing of water availability;
§ increasing precipitation in the form of rain rather than snow due to increasing temperatures;
§ smaller spring runoff volumes and/or earlier runoff that will impact water availability for irrigation and for ecological and species needs;
§ milder winters and hotter summers, resulting in longer growing seasons and increased plant and human water use;
§ increased evaporative losses from reservoirs, streamflows and soils due to hotter, drier conditions;
§ increased evapotranspiration by agricultural and riparian plants;
§ an increase in extreme events, including both drought and floods.

Incorporating climate change into water planning has historically been challenging due to the continued level of prediction uncertainty, coupled with the myriad additional pressures faced by water resource planners. Climate change needs to be added as “another pressure” along with population growth, changing demographics, existing climate variability, increasing water demand and availability challenges, land use, species protection and other ecosystem demands. Adaptive management strategies will need to be devised that are robust and flexible enough to address climate change.

Most of the strategies, policies and tools necessary to manage water resources in the context of climate change have probably already been identified. Incorporation of climate change into New Mexico’s water planning may require new modeling and scenarios, and may lead to adjusted priorities and revised timelines, including acceleration of “no regrets” strategies that will also ameliorate the other pressures on the State’s water resources.

Mainstreaming climate vulnerabilities and adaptation strategies into water resource management will be required for comprehensive planning for sustainable development.

By Martin Zehr on 2007 02 04