Senator Eliot Shapleigh - El Paso, Texas

With rising temperatures putting more pressure on Texas' water supplies, state policymakers should fold climate change into their planning, according to scientists who are meeting at the Capitol this week.

But even as the scientists marched through slide shows and urged the lawmakers to act, the appetite in the Legislature to tackle the issue remains an unknown.

The scientists, who had gathered for Climate Change Impacts on Texas Water, a conference organized chiefly by the River Systems Institute at Texas State University-San Marcos, said models were not yet good enough to predict exactly how climate change might affect the state.

But some of the scientists made their own predictions.

"Where it's wet, it's going to get wetter. Where it's dry, it's going to get drier," said Gerald North, a climate scientist at Texas A&M University.

Crop yields could decline by 40 percent, and ranchers might want to invest in heat-tolerant cattle, said Bruce McCarl, an agricultural economist from Texas A&M.

Average summer temperatures, which hovered around the high 70s from the 1960s through the 1990s, could rise into the 90s by century's end, said Katharine Hayhoe, an atmospheric scientist at Texas Tech University.

Forecasts for precipitation and groundwater supplies were less clear-cut, and scientists said most of the certainties pertained to polar regions.

The conference closes today with a session on state water policy in coming decades.

Lurking in the background was the issue of what responsibility Texas should take.

Producing 652.5 million metric tons in 2004, according to the latest data available, the Lone Star state is the nation's leading emitter of carbon dioxide, which scientists have linked to global warming.

Texas does not have caps on carbon dioxide emissions, and some lawmakers said they want to wait until the federal government takes action.

"It's a real mistake creating state-by-state policies with regard to global warming or greenhouse gases," said state Rep. Dennis Bonnen, R-Angleton, who chairs the House Environmental Regulation Committee.

Of the 12 bills filed last session that dealt directly with global warming, seven never received a hearing, and only one — which had as its narrow mission the study of water supplies and the Rio Grande — passed.

Since the 2007 session, House Speaker Tom Craddick, R-Midland, has appointed a committee, also chaired by Bonnen, to examine electrical generation and the environment.

Economic arguments have had more traction with leading lawmakers, and some groups, including the renewable energy industry, have tailored their message to be more persuasive.

However, there is little indication a major policy shift on global warming is likely when the Legislature reconvenes in 2009.

In a September speech, Gov. Perry criticized former Vice President Al Gore by saying, "I've heard Al Gore talk about man-made global warming so much that I'm starting to think that his mouth is the leading source of all that supposedly deadly carbon dioxide."

John Nielsen-Gammon, the state climatologist, said he has not briefed the governor on climate change and potential consequences for the state.

Though representatives of the governor's and lieutenant governor's office dropped by the conference, it was lightly attended by lawmakers.

However, the conference got a jolt from a lunch-time speech Monday from Larry Soward, one of three members of the Texas Commission on Environmental Quality, and a Perry appointee.

"As the nation's leading emitter of greenhouse gases, and with an extremely vulnerable coastline," Soward said, "it only seems reasonable and logical to me for us here in Texas to step up, take a leadership role and begin to seriously and meaningfully address our greenhouse gas emissions."