( CNN ) -- Environmentalists are encouraged by President Barack Obama 's focus this week on renewable energy and stricter emissions standards , although some economists are skeptical he can pull the country out of the recession while cleaning up the planet . President Barack Obama with Transportation Secretary Ray LaHood and EPA Administrator Lisa Jackson . Obama must strike a careful balance between stimulating the economy in the coming months and investing in the long-term future of the environment , said Raj Chetty , professor of economics at the University of California , Berkeley . `` If you spend money too quickly , you lose site of the long-term vision , '' Chetty told CNN . `` If you focus too much on the long term , you may not act on spending money . '' Framing his remarks with an eye on the recession , the president on Monday announced a plan for `` a new energy economy that will build millions of jobs . '' Obama proposes to put 460,000 Americans to work through clean energy investments , increasing fuel efficiency in vehicles and reducing greenhouse gas emissions . By 2025 , the Obama administration hopes one-fourth of the nation 's energy will come from renewable sources . Over the long term , the president hopes to create millions of new jobs by investing $ 150 billion in taxpayer money to help private companies develop new sources of clean energy , such as wind , solar and geothermal power . It 's about time , say scientists who often clashed with former President George W. Bush on environmental policy . `` By repowering our nation with clean energy , we will create millions of jobs that ca n't be sent overseas . By harnessing the energy of the sun and wind , we can refuel our nation and end our addiction to oil , '' said Wesley Warren , director of programs for the Natural Resources Defense Council . Environmental scholars , however , say the changes Obama seeks are not easy . `` These technologies are not new . They have been around for 10 to 15 years , '' said Bill Chameides , dean of the Nicholas School of Environment at Duke University . `` Government can push new policies , but it has to prove to be economically competitive or else it will not happen . '' `` It is going to require massive investments , '' said Joseph Romm , former acting assistant secretary of energy under the Clinton administration and senior fellow at the Center for American Progress . `` The only question is , are we going to be the leader and export our technologies or a follower and continue importing our resources ? '' Some economists question whether spending government money on new energy technologies is the best way to stimulate the economy in the short term . Opponents of Obama 's proposals say renewable energy would be expensive , take up large amounts of land , and might not even be able to generate sufficient energy given the aging infrastructure of the nation 's electric grid . `` If the private sector will not invest in these technologies , it will not be efficient , '' said Alan Reynolds , senior fellow at the Cato Institute . `` Creating jobs by switching from one form of energy to another is a bad idea , '' he added . `` You do n't need subsidies for anything that is free . Getting a $ 7,000 rebate on a $ 100,000 plug-in electrical hybrid that gets its power from a coal plant does n't make a lot of sense . '' Several events in Washington this week underscored the Obama administration 's commitment to environmental issues . Secretary of State Hillary Clinton on Monday named a special envoy to pursue global agreements combating global warming . On Wednesday , former Vice President Al Gore urged Congress to approve Obama 's stimulus package and said the United States needs to join international talks on a climate-change treaty . `` For years our efforts to address the climate crisis have been undermined by the idea that we must chose between our planet and our way of life , between our moral duty and economic well-being these are false choices , '' Gore told the Senate Foreign Relations Committee . `` In fact , the solutions to the climate crisis are the same solutions that will address our economic and national crisis as well . '' Obama may have science on his side . By overwhelming consensus , scientists agree that our warming planet poses a greater global threat with every passing day . The replacement of current technology with energy generated from natural resources , such as sunlight and wind , could help reduce CO2 emissions by 50 percent by 2050 , according to the International Energy Agency . `` Frankly the science is screaming at us , '' said Sen. John Kerry , chairman of the Senate Foreign Relations Committee , at Wednesday 's hearing . `` Carbon dioxide emissions grew at a rate of four times faster in the Bush administration than they did in the 1990s . '' Even so , experts agree the faltering economy will complicate any discussion about investment in clean energy . `` The country is running two deficits , '' said David Orr , a professor of environmental studies and politics at Oberlin College , `` the economy in the short term , which will take one to five years to figure out [ and ] the environment in the long term , which if we do n't do anything about it will see catastrophic effects . ''
Environmentalists are encouraged by President Obama 's focus on renewable energy . Some economists are skeptical he can fix the economy and the planet at once . Comment: Obama can push new policies , but they must be economically competitive . President announced a plan for `` a new energy economy '' that will build jobs .