The Rio Grande Valley is already experiencing the effects of this warming trend. The growing season here is approximately a week longer than it was in the 1960s. And a warmer climate in New Mexico will bring numerous environmental changes: Warmer temperatures will increase evaporation from reservoirs. Snowpack will decrease and the snow line will move higher in elevation and further north. Snows will also start later and end earlier.
“I’m interested in water issues in the Southwest, and one of the things we’re starting to see in the data is a trend toward temperature-driven decreases in stream flow,” Gutzler says. He also is currently working with the IPCC on its fifth assessment and will be one of the lead authors for a chapter on climate change detection and adaptation. Variability remains in the record, he says, but scientists have just started to see the first decade or two’s worth of changes in the data between snowpack and evaporation and stream flow rates.
“That’s totally consistent with what the models say will happen in a very serious way as the 21st century proceeds, and I don’t think the Southwest can afford that,” he says. “I think there is a very real prospect that stream flows could diminish very significantly over the course of the century—and how the Southwest deals with that in the face of increasing population, I think, is a very scary prospect.”
As a result of treaties and contracts, New Mexico shares Colorado River water with six other states, and the Rio Grande’s waters with Colorado, Texas and Mexico. The state’s second largest river, the Pecos, flows into Texas.
Already, there are interstate conflicts over water use and, in dry years, New Mexico must carefully control water use by irrigators. Rather than keeping water in the Pecos River or Rio Grande for conservation purposes and to ensure the survival of fish and other species, the water use is set to guarantee there is enough water for downstream users in Texas. Experts already are predicting that the Colorado River Compact—the agreement by which the Colorado River Basin’s water is tallied among seven states—will become unenforceable by the mid- to late-21st century.
As surface water flows continue to decrease in the future, this will surely become more complicated. Melting glaciers in the Himalayas are affecting water supplies in Asia, Indian environmental journalist Joydeep Gupta says.
“It’s not an easy thing to plan for: There is an increase in the water supply and then a gradual decrease, the relative amount of which is unknown,” he says. “Water is a security situation—all of us are aware of how important it is to a country’s security.”
The water situation in the southwestern United States, he says, is severe:
“I think it is so severe that for anyone to not be worried about it is simply stupid,” he says, adding that engineers working on the hydrological calculations for new dams must realize their basic water flow assumptions are no longer valid—and that changes everything. “You assume you have 3 million acre-feet of water, and you’re actually getting 2 1/2,” he says. “So your entire design, everything, goes wrong.”
No matter if the view is from Cancún or Santa Fe, addressing climate change requires a long-term view, Gutzler says. And that’s part of what makes it so difficult: Political structures are not designed to effectively deal with long-term issues. “That’s a very hard thing to do, in the United States, certainly,” Gutzler says, “and for the rest of the world, as well.”
But as always, Gutzler is thinking like a scientist.
“Having said that, nature is just going to do whatever it does. Everything we’re saying in the scientific community: It’s all a testable hypothesis, sooner or later,” he says. “It’s just that doing nothing may have profound consequences if some of those projections play out.”
At the late-night closing plenary on Friday, Dec. 10, delegates from countries worldwide speak of transparency, compromise and an agreement that wasn’t perfect, but was balanced and a step in the right direction. Delegates from both developing and industrialized countries praise the UN process—a show of solidarity clearly intended to prove that the process itself is valid and worth maintaining. Delegates return to closed-door meetings and emerge in the early hours of the morning with the texts of their labor.
The final agreement—approved by all nations save for Bolivia—does not contain legal mandate for industrialized nations to cut their carbon emissions. It establishes a Green Climate Fund, but doesn’t solidify from what sources the funding will come. The Cancún Accord avoids establishment of the Kyoto Protocol’s second commitment period.
All of these issues were punted—they will be revisited at next year’s conference in Durban, South Africa. SFR