As climate negotiations got underway in Paris, climate politics intensified in Washington on Tuesday, where the House Committee on Science, Space and Technology convened a hearing with a tell-tale title: "Pitfalls of Unilateral Negotiations at the Paris Climate Change Conference."

Committee Chairman Lamar Smith did not mince words about his intentions. “Today’s hearing will demonstrate that the President’s UN climate pledge is destructive to the American economy and would produce no substantive environmental benefits” he said. (See House video starting at 7:40).

As the majority party, Republicans set the agenda and invited three witnesses: Oren Cass, senior fellow at the Manhattan Institute for Policy Research; Andrew Grossman, an associate at Baker & Hollister, a law firm; and Bjorn Lomborg, president of the Copenhagen Consensus Center.

The fourth witness was WRI President and CEO Andrew Steer.

“As I listen to the testimony today I hear three messages,” Steer said. “That action against climate change will cost too much, that it will hurt economic growth, and that the climate deal under discussion in Paris won’t achieve much.” (Video, 31:30)

In response to the first two criticisms, Steer cited the findings of the New Climate Economy report of the Global Commission on the Economy and Climate. The commission was led by former president Felipe Calderon of Mexico, he noted, and an advisory group consisting of some of the world’s top growth economists oversaw the technical quality of the work . On the costs of climate action, the Commission concluded that globally, investment costs in a low-carbon future would rise slightly, by around 2 percent, he said. But when the savings from recurrent costs—such as lower energy costs from increased efficiency—are included, the low-carbon path would actually be around 2 percent cheaper. (For details on low-carbon growth in the United States, read Seeing is Believing: Creating a New Climate Economy in the United States.)

As for the impact on economic growth, Steer said the study found that “smart policies to address climate change will promote competitiveness and growth” through increased efficiency, faster innovation, reduced costs from congestion and pollution, and greater policy predictability, “something that private investors crave.”

“Finally, climate-smart policies also reduce the negative impact on growth of climate change itself, which, unchecked will be very substantial,” Steer said.

He added that synergies between climate action and growth explain the growing number of corporations that are urging bold action in Paris and adopting science-based targets for reducing their own emissions; and why 360 cities worldwide—including more than 100 in the United States—have signed on to the Compact of Mayors, committing to track and reduce their emissions.

It also explains, he said, why India Prime Minister Narendra Modi has set the goal of massively raising India’s solar capacity from its current level of 4 gigawatts (GW) to 100 GW by 2022. “He didn’t do this because he’s a member of the Sierra Club, but because he rightly believes that it will benefit his nation’s economy,” Steer added.

On the third question – how much impact will the Paris deal have – Steer cited WRI analysis showing that climate actions from the 183 countries that have submitted their Intended Nationally Determined Contributions (INDCs) so far “will make a substantial difference in stopping climate change.”

“We have analyzed more than a dozen recent studies that added up the contributions of INDCs. They put us on track for a world that warms by 2.7-3.7°C over the next century, depending on modelling assumptions, compared to 4-5°C of warming under a business as usual path. This is significant progress, but not enough,” he said.

As for whether the U.S. administration can deliver on the emissions-reduction pledges it has put forward ahead of Paris, Steer cited recent WRI research, Delivering on the U.S. Climate Commitment, that shows several pathways to get there.

“In closing,” Steer said, “we believe that U.S. political and technical leadership in solving the great challenge of climate change is absolutely necessary. As with many other challenges before, the United States is the indispensable leader. We also believe that the United States will benefit economically from playing such a role.”

I wish I could report that Steer’s testimony changed hearts and minds of those who had called the hearing. If it did, the impact was not evident.

A rhetorical high point came when Lomborg asserted that climate-associated sea level rise would not be a major problem, even in low-lying, highly populated developing countries like Bangladesh, because people would build levies, as the Dutch have done, prompting an incredulous response from one of the minority party congressmen.

Later that day, the House was scheduled to follow the Senate in voting to block the Clean Power Plan (CPP) that is at the heart of President Obama’s climate action plan and thus, of the ambitious pledges that the United States is putting forward in Paris. Obama has said he will veto the bills.

In doing so he would appear to have the broad support of the American people: This week, a new New York Times/CBS News Poll found that two-thirds of Americans want the United States to join a Paris climate change pact.