Climate change cannot be denied. The inconvenient truth President Barack Obama refuses to accept is that U.S. efforts to significantly alter its course are fruitless and severely handicap America's ability to cope with its consequences.

The global climate has gone through profound cycles of cooling and warming cycles since long before humans walked the earth. Still, the majority of qualified scientists have now concluded industrial activities - greenhouse gas emissions - are now the most significant cause of global warming and are urging concerted international action.

CO2 composes 80 percent of harmful emissions. Failing to win congressional approval for a system of permits to reduce emissions, the president has unilaterally targeted coal-fired electric utilities and fuel use in transportation to reduce U.S. emissions by 17 percent from 2005 levels.

Those actions are unnecessary and harmful.

In recent years, more abundant and cheaper natural gas has motivated electric utilities to switch from coal, and energy intensive manufacturers in metals, chemicals and the like have made remarkable, cost-saving progress to reduce energy use.

Responding to consumer preferences, automakers were making more fuel efficient vehicles before the president imposed more stringent mileage standards.

The high cost and stress of commuting are encouraging many young people to live closer to jobs. Competition from rail is pressuring trucking companies to purchase more fuel efficient rigs.

Together, those free market decisions have reduced CO2 emissions by more than 9 percent from 2005 levels.

Now, the EPA and other federal agencies want to micromanage those choices by imposing inflexible standards on electric utilities and other manufacturers. Progressives would happily force as many Americans as they can onto mass transit, imposing a terrible drain on state transportation and local operating government budgets.

Those initiatives would not do much to arrest global warming, and by increasing taxes and production costs would simply send more jobs to China.

With an economy about half the size, China already emits almost twice the CO2 as either the United States or Europe. Every 18 months, its emissions grow enough to replace the emissions savings the United States will accomplish hitting the president's 15 year target. Other developing countries, like India, are similarly adding to the problem.

Progressives propose to bring China and other nations along through diplomacy but despite considerable effort, the president has not been able to obtain Beijing's cooperation on climate change, its undervalued currency, or just about anything else that would constrain the Middle Kingdom's growth.

Put bluntly, if manmade emissions are the culprit, then by China's actions alone global warming is going to happen with the force and fury many fear. The United States can do little to stop it.

Since the beginning of this century, U.S. growth has slowed to 1.7 a year - down from 3.4 percent the prior two decades -thanks largely to U.S currency and trade policies toward China that artificially advantage its manufacturers, restrictions on offshore oil and gas development that keep America dependent on imports, and costly and ineffective regulations on banking, health care and other industries.

Millions of Americans are without decent jobs, and governments at all levels are severely challenged. Those will get worse if the nation continues on its current path.

Rising temperatures will confront federal and state agencies with unparalleled challenges, as droughts dislocate cattle ranchers in the Southwest, insects threaten forests, arable regions shift north, rising sea-levels flood coastal cities, and new diseases attack humans, plants and animals.

Moving populations and economic activities will cost trillions of dollars, and an economy impoverished by mindless micromanagement from Washington simply won't be able to generate the tax dollars to foot the bill.

Peter Morici is an economist and business professor at the University of Maryland.