President Barack Obama on Tuesday proposed wide-ranging initiatives to reduce carbon dioxide from power plants, moves that will likely have a big impact on states like Ohio where coal remains the primary source of electric power.

In a speech at Georgetown University, Obama emphasized the threat from climate change, saying he will launch the first federal regulations on carbon dioxide emitted by power plants as a way to reduce the gases blamed for global warming.

“As a president, as a father and as an American, I’m here to say we need to act,” Obama said.

The presidential memo accompanying Obama’s plan will direct the Environmental Protection Agency to have a proposal establishing carbon pollution standards for operating power plants by next June.

Forty percent of U.S. carbon dioxide emissions, and one-third of greenhouse gases overall, come from electric power plants, according to the federal Energy Information Administration.

In Ohio, coal burning generated 77.8 percent of state electricity in 2011, followed by nuclear power at 11 percent and burning natural and other gases at about 9 percent. The remainder is from solar, wind and other sources, according to the Public Utilities Commission of Ohio, or PUCO.

Large solar and wind projects are in the works that should alter that breakdown. Ohio law requires that 25 percent of electricity sold by electric distribution utilities or services companies must be generated from alternative energy sources by 2025.

As an example of how coal-dependent Ohio is today, AES disclosed in its latest financial filing in May that Dayton Power & Light Co. gets 97.3 percent of the electricity it generates from coal. The burning of the coal produces 14 million tons of green house gas emissions annually, AES said.

“If we are required to implement control of (carbon dioxide) and other (green house gasses) at generation facilities, the costs of DPL and DP&L of such reductions could be material,” the company said in its Form 10-Q.

At Duke Energy, which supplies the Cincinnati metro area, 44 percent of energy comes from coal, 34 percent nuclear and 21 percent natural gas in the six states where it supplies retail power.

FirstEnergy, the parent company of Ohio Edison which serves Springfield, generates 64 percent of its electricity with coal, 18 percent with nuclear, 6 percent with natural gas, and 10 percent with hydro-electric and wind.

“We are currently deactivating a number of older, less efficient coal-fired plants, and once these units are no longer in service, nearly 100 percent of the power we generate will come from low or non-emitting sources including nuclear, natural gas, scrubbed coal, and renewable energy,” a spokeswoman said, adding that FirstEnergy is on track to reduce its greenhouse gas emissions by 18 percent by 2015 — five years ahead of President Obama’s goal to reduce such emissions by 17 percent over 2005 levels.

Robert M. “Mike” Duncan, president and CEO of the American Coalition for Clean Coal Electricity, declared: “This is going to be a legacy issue for the president, a legacy of higher energy costs, lost jobs, and a shattered economy.”

Ohio Senator Rob Portman, a Republican, also denounced the move.

“President Obama’s EPA overreach has already cost jobs in Ohio,” he said. “At least eight coal fired power plants in Ohio are set to close due in large part to regulatory mandates put in place by the EPA. As a result, nearly a thousand Ohio jobs will be directly impacted, local communities will lose millions in tax revenue, and more than 6,000 megawatts — enough energy to power thousands of homes — will be taken off the grid.”

House Speaker John Boehner, R-West Chester, said “these policies, rejected even by the last Democratic-controlled Congress, will shutter power plants, destroy good-paying American jobs and raise electricity bills for families that can scarcely afford it.’’

Ohio Sen. Sherrod Brown, a Democrat, said that “it’s critical that we reduce greenhouse gas emissions, but we must do this in a way that creates Ohio jobs rather than puts them at risk. We must make sure that industries in other nations are operating under the same rules as our domestic manufacturers. We must develop global solutions that are both comprehensive and fair to Ohio workers and manufacturers.”

Alden Meyer, strategy and policy director at the Union of Concerned Scientists, said there’s no time to lose.

“President Obama has a little more than three years to cement a lasting legacy on climate change, and he’ll need every last second. Americans are already dealing with worse droughts, wildfires, and coastal floods, and the practical realities of climate change are forcing political leaders to make this a priority,” Meyer said.

Obama plans to expand permitting for renewable energy projects on federal land, enough to provide electricity for six million homes by 2020. That would double the electric capacity federal lands now produce, said senior administration officials quoted by the Associated Press. He’ll also set a goal to install 100 megawatts of energy-producing capacity at federal housing projects by the end of the decade, the officials added.

“While no single step can reverse the effects of climate change, we have a moral obligation to act on behalf of future generations,” the White House said in a statement, arguing that climate change is no longer a distant threat because the 12 hottest years on record all occurred in the past 15 years, the AP reported.