Environmental Protection Agency Administrator Gina McCarthy defended the Obama administration's climate agenda during a Thursday House hearing, saying a warming planet creates a "serious public health and economic problem."

McCarthy said that climate change and runaway carbon pollution have exacerbated asthma complications, extended allergy seasons and helped spread diseases uncommon to regional climates. She said forthcoming EPA emissions regulations for new and existing power plants, as well as ones on mercury and other pollutants, would address those issues.

"Things are changing, and things are not changing for the best in terms of public health," McCarthy told the House Science, Space and Technology Committee.

The Obama administration has said the emissions rules would save billions of dollars in health care costs and help curb extreme weather that some have linked to climate change.

But Republicans and industry officials contend the administration's climate policies will raise energy prices and stunt the economy.

The panel's Republicans slammed McCarthy and the EPA, saying the agency hasn't done enough to publicize the data it uses to calculate the health benefits of the rules it designs.

"Nearly all of this administration's air quality regulations are justified on the basis of hidden data. These regulations cost billions of dollars, but the EPA claims that the benefits of these rules justify for the costs," said committee Chairman Lamar Smith, R-Tex..

Smith added that he plans to introduce legislation that would stop the EPA from basing regulations on "undisclosed and unverified information."

The EPA, however, has said the data the committee is seeking cannot be handed over because of privacy concerns.

The committee wants to get data that was used in outside studies the EPA consulted when designing various regulations — not studies that the EPA conducted itself.

"All of that information isn't available to the EPA," McCarthy said.

Collecting and handing over the data would not only be difficult, but it also would violate agreements to not share personally identifiable information the study participants struck with outside grantees, the EPA has said.