Visit yes, but do you want to live there?

Posted on January 27th, 2013 in Climage Change,Science by Robert Miller

Fig 1. Projected changes in median runoff for 2041-2060, relative to a 1901-1970 baseline, are mapped by water-resource region. Colors indicate percentage changes in runoff. Hatched areas indicate greater confidence due to strong agreement among model projections. White areas indicate divergence among model projections.

We have entered into a phase of global climate change where our ability to predict future weather patterns can no longer be based on past weather experience. We will still have four seasons, but an earlier intrusion of spring, an extended fall,  warmer winters, and hotter summers are likely to become even more pronounced in the coming decades. The time with which we might have mitigated and reversed the forces behind global climate change has passed. We are now faced with the challenge of adapting to the coming changes brought about by the anthropogenic  carbon dioxide levels in our atmosphere that began to accumulate with the dawn of the industrial revolution. Our incapacity to alter the level of greenhouse gases endangers our planetary future, as we have entered into the phase where we must adapt to the inevitability of climate change, with only hints so far at the full range of the problems we must address to keep our economy in high gear, while we transition to a culture more compatible with the many changes we face that are just now on the horizon. Obama’s inaugural speech indicated a fresh commitment for addressing these problems, but serious obstacles remain in our political system of governance that will make significant changes difficult to achieve; we will receive an early indication about the seriousness of Obama’s commitment when he decides whether to continue with the XL pipeline project.

The National Research Council (NRC; a division of the National Academy of Sciences) has recently released a report, encouraged by a contingent of Federal Agencies that requested an analysis on how to improve weather forecasting and facilitate shared modeling information on a broader scale, with decadal weather modeling rather than the millennial models that are generally produced by the Intergovernmental Panel on Climate Change (IPCC). This recent report emphasizes the need for broader sharing of data from different modeling strategies and the development of application tools (APPS) that can be used to convert results from one modeling strategy into a form of data that can be more widely shared and serve as input data for other models. As we move into the period in which historical weather patterns are less useful, models based on continuously updated meteorological data, will have to be developed to help guide farmers to optimize crop selection and whole societies that must become more acutely aware of changes in sea levels and plan accordingly. An increase in sea level was certainly a factor in the destructive force of hurricane Sandy last year. Information such as this is also useful for appropriate selection of our vacation sites for both time and location as well as the regions where we want to live. Water availability and water quality will become more critical and undoubtedly issues such as the privatization of water will move from the back sections of our newspapers to the front pages. Water wars are already underway and water priorities (farmers vs urban dwellers) will have to be renegotiated. Can we abandon irrigation water for farmers to insure adequate water supplies for urban dwellers? These are unavoidable issues if these trends continue as projected.

Another source of useful information is the United States Global Climate Change Research Program (USGCRP) from whose 2009 report, Fig 1 was taken; this figure also appeared in the new NRC report. It shows the midcentury projections (2141-2160) for runoff (meaning the source of river runoff) from modeling data based on the current trends of global warming conditions and compared to the records for runoff from 1901-1970. What stands out is the projection for Southwest region of the country in general, but more specifically, the state of Arizona seems particularly vulnerable to changes in runoff water. Arizona is already a parched land, but it is projected to become even more so with a 20 to 40 percent decline in runoff. Currently Arizona gets its water from intrinsic runoff through the Salt River Project (SRP), which includes contributions from the Salt, Verde, Gila and Agua Fria rivers, from the Colorado River Basin (Central Arizona Project; CAP) that also supplies many other states in the Southwest and ground water aquifers that currently supply 43 % of the water for Arizona residents.  A loss of 20 to 40 percent in river runoff is a big number and a decline of that magnitude will impact on all the current sources of water for Arizona.  As the air warms, it can hold more moisture, such that the dry air of the Southwest will increasingly remove moisture from the already arid conditions of the soil, which, through precipitation (and a seemingly unholy alliance), will contribute to increased runoff in other regions of the country, including the Northeast and Midwest, areas projected to see an increase in runoff water. Hot air moisture absorption will also accelerate evaporation from water storage in dams, and decrease water availability in aquifers (the water table will go down, such that many wells will demand deeper drilling). Note that the Southern region of the United States is not colored because different models don’t converge sufficiently to make midcentury projections meaningful: more work is needed for runoff projections of the South. Some people will look at this map and conclude that water has to be moved from the Midwest to the Southwest and plans have already been drawn up to pump Mississippi flood water to the Colorado region to compensate for the decline in the Colorado River basin runoff that supplies water to much of the Southwest. Whether this will ever be built is an open question.  Perhaps some may look at these figures and still conclude that Arizona will forever be a great place to live and that someone will make sure that there will always be sufficient water. Others however will look at these projections and decide that Arizona is a great place to take a winter vacation, while moving the state far down the list of desirable places to live. I fall into the latter category: if nothing else, the threats of global climate change have forced upon our brains additional pressure to think more longitudinally! If we don’t annihilate ourselves as a species, perhaps this new pressure for long-term thinking will evolve bigger brains in humans and then everyone will realize the true threat we face for planetary survival of Homo sapiens and act with a more uniform dedication to the mission in front of us. The coming changes we can anticipate from the forced warming of our planet are not just related to water, but involve a whole panoply of new challenges ranging from the loss of coral reefs from acidification of the oceans, dramatic changes in forest species, more wildfires especially in the Southwest and threats to the survival of many different species. One can hope that as the threats from  global climate change come more sharply into focus, they will become a force for unifying the country to mobilize our energies like we did during WW II. Right now we live in a destabilized society. The science of global climate change has become so politicized, that we react to devastating storms only after they have occurred and so far, we are doing very little to either adapt or minimize their intensity in the future. Hurricane Sandy will force adaptation on the part of some home owners because insurance rates will become high enough that some will no longer afford to live there. But are we willing as a society to have the sole means of adaptation delivered to us through changes in insurance rates? Are insurance companies the pied pipers of global climate change?



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