Washington (AFP) - NASA pushed back against a congressional proposal to slash more than $300 million in funding from its branch focused on climate issues.

The proposal would cut funding to NASA's Earth Sciences division, which researches the planet's natural systems and processes -- including climate change, severe weather and glaciers.

Republican Lamar Smith, who chairs the House of Representatives' Science, Space and Technology Committee presented the proposal earlier in the week.

NASA administrator Charles Bolden said that the bill "threatens to set back generations worth of progress in better understanding our changing climate, and our ability to prepare for and respond to earthquakes, droughts, and storm events."

"In addition, the bill underfunds the critical space technologies that the nation will need to lead in space, including on our journey to Mars," he said.

NASA's Earth Sciences division currently has a budget of $1.9 billion.

Christine McEntee, executive director of the American Geophysical Union, wrote in a letter to Smith that her organization was "extremely concerned that the reauthorization significantly cuts funding for NASA's Earth Science Division."

The Republican-majority House committee said in a statement that the move was an attempt to "restore balance to NASA's budget" by putting more emphasis on space exploration.

"We must continue to invest in NASA as the only government agency responsible for space exploration," it said.

Republican Senator Ted Cruz, who chairs the Senate Subcommittee on Space, Science and Competitiveness, emphasized a similar desire to refocus NASA activities on space over Earth sciences during hearings last month.

Democratic Congresswoman Eddie Bernice Johnson, the House committee's ranking member, criticized what she called an attack against climate science.

"In order to serve an ideological agenda, the majority is willing to slash the science that helps us have a better understanding of our home planet" she said in The Hill, a Washington newspaper covering Congress.

In January, NASA announced that 2014 had been the warmest year on the planet since 1880.