Texas Gov. Rick Perry stirred up a fresh scientific spat today with his claim that scientists were manipulating their data about climate change "so that they will have dollars rolling into their projects" — a view that serves to highlight the differences among the GOP presidential candidates on science-related issues.

During a town hall meeting in Bedford, N.H., here's what Perry, one of the front-runners for the Republican nomination, had to say about the state of climate science:

"I do believe that the issue of global warming has been politicized. I think there are a substantial number or scientists who have manipulated data so that they will have dollars rolling into their projects. I think we're seeing, almost weekly or daily, scientists are coming forward and questioning the original idea that manmade global warming is what is causing the climate to change. Yes, our climate has changed. They've been changing ever since the earth was formed. But I do not buy into a group of scientists who have in some cases [been] found to be manipulating this information. ..."

The comments are pretty much in line with what Perry has said in the past. He's playing off the suspicions raised by the "Climategate" e-mail controversy that broke in 2009. That flap revealed that the most outspoken climate researchers are all too human when it comes to talking about their intellectual adversaries in private — but in the end, they were mostly cleared of scientific malfeasance (although one published graph was judged to be "misleading").

The criticisms of Perry's view follow well-worn tracks as well: On the left-leaning Think Progress blog, Texas A&M climate researcher Andrew Dessler is quoted as saying that none of the credible atmospheric scientists in Texas agree with the governor. "This is a particularly unfortunate situation, given the hellish drought that Texas is now experiencing, and which climate change is almost certainly making worse," he said.

Think Progress goes so far as to list more than three dozen scientists who disagree with Perry.

Brian Snyder / Reuters

Texas Gov. Rick Perry extends his arm toward a lab worker during a tour of Resonetics Laser Micromaching in Nashua, N.H., on Wednesday. Resonetics CEO Chris Banas is to the left of Perry, and Cliff Gabay, the company's president, looks on from the right.

The Texas governor's views come in contrast with those of former Massachusetts Gov. Mitt Romney, an early front-runner in the GOP presidential field. Romney has said "I believe, based on what I read, that the world is getting warmer" and added that "I believe that humans contribute to that."

As a result, he said at a New Hampshire town hall meeting in June, "it's important for us to reduce our emissions of pollutants and greenhouse gases that may be significant contributors." However, he said any measures to stem greenhouse gases should be applied on an international basis. He opposed putting a carbon cap-and-trade system into place because it would put America at a competitive disadvantage.

The Perry vs. Romney climate split may be the latest and buzziest difference to emerge in the race for the GOP nomination, but when you look closely at the candidates, you'll see other differences as well. Here's a rundown on four of the leading candidates, related to four hot-button scientific topics: climate policy, evolution education, stem-cell research and science funding:

Climate policy:

We've already summarized Perry's and Romney's views.

U.S. Rep. Michele Bachmann of Minnesota opposes climate change legislation, saying that carbon dioxide is a "harmless gas." During a town hall meeting in South Carolina this week, she said that all the issues surrounding climate change would have to be "settled on the basis of real science, not manufactured science."

U.S. Rep. Ron Paul of Texas has called the concern about Earth's changing climate "the greatest hoax I think that has been around for many, many years, if not hundreds of years," based on the Climategate reports (see above). He's opposed to energy subsidies as well as government efforts to control greenhouse-gas emissions. "Pollution can be better taken care of under a private market system, under private property," he said.

(President Barack Obama, by the way, favors policies to reduce greenhouse-gas emissions, but the current "climate" in Congress has severely limited any progress on environmental initiatives.)

Evolution education:

Perry says he is a "firm believer in intelligent design as a matter of faith and intellect, and I believe it should be presented in schools alongside the theories of evolution." Intelligent design is the view that the complexity seen in nature is best explained as resulting from the efforts of an intelligent designer — for example, God, or an alien civilization. But in Perry's case, certainly God.

Romney said during his presidential campaign that he believes "God designed the universe" and that he believes God "used the process of evolution to create the human body." As Massachusetts governor, he opposed the teaching of intelligent design in public-school science classes. "The science class is where to teach evolution, or if there are any other scientific thoughts that need to be discussed," he told The New York Times. "If we're going to talk about more philosophical matters, like why it was created, and was there an intelligent designer behind it, that's for the religion class or philosophy class or social studies class."

Bachmann says "evolution has never been proven" and believes that intelligent design should be taught alongside the evolutionary view of biological change. "What I support is putting all science on the table and then letting students decide," Bachmann told reporters at the Republican Leadership Conference in New Orleans in June.

Paul says "nobody has concrete proof" for evolutionary theory, although he acknowledges that "it's a pretty logical theory." In his view, the intelligent-design concept has more to do with personal beliefs rather than science. "In a libertarian society these beliefs aren't nearly as critical. When you have government schools, it becomes important," he said. "'Are you fair in teaching that the earth could have been created by a creator or it came out of a pop, out of nowhere?' In a personal world, we don't have government dictating and ruling all these things; it's not very important."

(Obama favors the current legal view that teaching the intelligent-design concept in public-school science classes would be unconstitutional.)

Stem-cell research:

Perry is opposed to human embryonic stem-cell research, which involves destroying human embryos to harvest the therapeutic cells. But he's a strong supporter of less controversial adult stem-cell research. In fact, he was a beneficiary of such research when he received an infusion of his own lab-grown stem cells to speed recovery from a back injury.

Romney has voiced support for embryonic stem-cell research in the past, but he says his position has changed over the years, and he now opposes such research.

Bachmann is opposed to federal funding for embryonic stem-cell research, but favors less controversial initiatives that use adult stem cells or reprogrammed cells (also known as induced pluripotent stem cells or iPS cells).

Paul says the federal government should have no jurisdiction over the conduct of embryonic stem-cell research. He has, however, sponsored legislation that would use tax credits to encourage less controversial stem-cell studies, as well as the establishment of stem-cell and cord-blood banks.

(Obama has favored expanded federal funding for embryonic stem-cell research — an issue that has been tied up in lengthy legal proceedings. Most researchers hope that reprogrammed cells will eventually provide a way out of the moral and ethical controversy.)

Science funding:

Federal funding for the National Science Foundation has become something of a hot potato in some GOP quarters, in light of recent criticism of the agency from Sen. Tom Coburn, R-Okla.

Neither Perry nor Romney has made his views on NSF funding widely known, but in the past the Texas governor as well as the Massachusetts governor have touted NSF grants that came to institutions in their states.

Bachmann has faced criticism from the right-leaning Club for Growth for her "questionable" vote to reauthorize spending by the NSF. However, Bachmann did recently seek to reduce NSF funding to 2008 levels for a budget reduction of $1.7 billion.

Paul voiced strong opposition to federal funding for science education in 2000, saying that "Congress has no constitutional authority to single out any one academic discipline as deserving special emphasis." More recently, Paul was one of two members of Congress voting against a resolution to mark NSF's 60th anniversary.

(After he took office, Obama vowed to double NSF's $6.5 billion budget, but this year's $6.8 billion figure falls well short of that goal.)

What to add?

I realize I'm missing many other worthy GOP candidates, and many other worthy issues relating to science and technology. Feel free to add your comments about the candidates and the issues, but please keep the conversation civil. This isn't the place to talk about the debt crisis, or chew over the immigration issue, or handicap the horse race. That's what the First Read blog is for. Check in with First Read and msnbc.com's Politics section for daily coverage of the 2012 presidential campaign.

Update for 10:30 p.m. ET Aug. 18: Former Utah Gov. Jon Huntsman, another GOP presidential hopeful, stirred the pot by sending along this Twitter tweet: "To be clear. I believe in evolution and trust scientists on global warming. Call me crazy." This follows up on The Washington Post's quote from Huntsman's chief strategist, John Weaver: "We're not going to win a national election if we become the anti-science party."

Although Huntsman accepts the view that greenhouse-gas emissions are contributing to climate change, he told Time's Swampland blog in May that cap-and-trade systems haven't worked and that "putting additional burdens on the pillars of growth right now is counterproductive."

On the stem-cell issue, a spokesman for Huntsman told LifeNews.com that the Republican supports research that involves "adult stem cells, non-embryonic stem cells and certain types of embryonic stem cell[s]" but does not support federal funding for research on new lines of embryonic stem cells. Such a stand appears to be consistent with the policy that was in place during George W. Bush's tenure at the White House.

Huntsman has generally been supportive of science funding: Among the efforts he supported as governor was the Utah Science Technology and Research Initiative at the University of Utah.

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