Washington ( CNN ) -- Top Democrats put the issue of climate change back in the spotlight Tuesday , debating legislation to cut greenhouse gas emissions while announcing $ 3.4 billion in new clean energy funds . A key congressional committee began hearings on a `` cap-and-trade '' bill requiring emissions to be cut by more than 80 percent over the next four decades . Questions related to global warming have been among the most politically contentious in recent years . Democrats are generally more receptive to proposals designed to curb energy consumption in order to slow climate change ; leading Republicans continue to express concern about the necessity and economic impact of such measures . President Obama has made the push for greater investment in a clean energy agenda one of his top domestic priorities . Attempting to move that agenda forward , the Senate Environment and Public Works Committee kicked off hearings on the Clean Energy Jobs and American Power Act . Supporters say the bill would reduce nationwide greenhouse gas emissions 20 percent by 2020 and 83 percent by 2050 through a cap-and-trade program under which companies would buy and sell emissions credits . Almost one-third of the credits would be given away to the electric power sector through 2026 in an effort to diminish negative economic effects . Leading Democrats have expressed optimism that the bill would help stimulate the creation of new `` green energy '' jobs . The measure is similar to a climate change bill narrowly passed by the House of Representatives in June . Scientists `` tell us that we have a narrow window of time in which to avert the ravages of global warming , '' said Sen. Barbara Boxer , D-California . Boxer , who chairs the environment committee , called the legislation `` our best insurance against a dangerous future . '' It is `` a responsible approach that sets attainable goals for gradual reductions in carbon emissions , and it protects consumers , businesses and workers as we move toward clean energy , '' she said . Committee Republicans tore into the measure . It is `` a tax , and it will mean more economic pain and suffering and fewer jobs , '' warned Sen. James Inhofe , R-Oklahoma . `` The victims of cap-and-trade ca n't just move on and get new , green jobs . The transition will mean leaving high-paying jobs , moving away from hometowns and significant reductions in lifetime earnings , '' he said . Administration officials testified on behalf of the bill , including Energy Secretary Steven Chu , Transportation Secretary Ray LaHood , Interior Secretary Ken Salazar and EPA Administrator Lisa Jackson . In all , 54 witnesses are scheduled to testify on the bill over the next three days . Obama , meanwhile , unveiled what the White House called the largest energy grid modernization investment in American history . At a Florida solar energy center , the president announced $ 3.4 billion in Smart Grid Investment Grant awards . `` By facilitating the creation of a clean energy economy , building this 21st century energy infrastructure will help us lay a foundation for lasting growth and prosperity , '' Obama said . The White House said the awards , which are being funded through the $ 787 billion stimulus act , will fund `` a broad range of technologies that will spur the nation 's transition to a smarter , stronger , more efficient and reliable electric system . '' Among other things , the awards will help support the installation of `` smart meters '' designed to help consumers monitor and control their energy consumption . The awards , going to 100 private companies , utilities and cities , will be divided into grants ranging from $ 400,000 to $ 200 million . They will be matched by $ 4.7 billion in private sector funds . Vice President Joe Biden also highlighted the issue of global warming Tuesday , visiting a former General Motors plant in Delaware that is being converted to allow for the production of plug-in hybrid electric vehicles . The plant is being purchased by California-based Fisker Automotive for an estimated $ 18 million . The new climate change push is being made against a backdrop of broad public support for federal action to slow global warming . Six in 10 Americans support a cap-and-trade proposal to cut pollution , according to a new CNN/Opinion Research Corp. survey . Thirty-seven percent are opposed to such a plan . The survey indicates a generational divide , with 68 percent of Americans under age 50 supporting cap-and-trade , but those 50 and older split on the issue . `` This is one more example of the growing generation gap that is shaping politics and policy in this country , '' said Keating Holland , CNN polling director . `` Younger Americans voted for Obama and tend to welcome change . Older Americans were less enamored of change in the 2008 election , and senior citizens were the only age group that voted for John McCain . '' The poll also suggests a partisan divide , with three in four Democrats backing the proposal and nearly six in 10 independents on board as well , but only four in 10 Republicans supporting `` cap and trade . '' `` Independents believe in global warming and believe that the government can take steps to curtail the problem , '' Holland said . `` But the environment is not a big priority for independents , as it is with Democrats . '' The CNN/Opinion Research Corp. poll was conducted October 16-18 , with 1,038 adult Americans questioned by telephone . The survey 's sampling error is plus or minus 3 percentage points . CNN Deputy Political Director Paul Steinhauser contributed to this report .
Senate Environment and Public Works Committee debates act to reduce greenhouse gases . President unveils Smart Grid Investment Grant awards to renewable energy systems . $ 3.4 billion in grants seeks ` ` smarter , stronger , more efficient and reliable electric system '' Climate change push being made amid broad public support for reducing global warming .