The United States' Environmental Protection Agency ruled today that man-made greenhouse gases are deteriorating the natural balance of the planet's atmosphere, changing its climate and therefore threatening the health of Americans.

The announcement comes as world leaders meet in Copenhagen, Denmark for a long-awaited climate change conference.

The finding is seen as an indicator that the EPA is prepared to take control measures on greenhouse gases in the U.S. to stave off climate change and push for the adoption of greener technologies.

Some business groups who oppose such regulation say it will worsen circumstances for Americans by increasing costs for manufacturers, raising energy prices and reducing jobs.

Read below EPA's administrator Lisa Jackson full remarks:

Administrator Lisa P. Jackson,

Remarks on the Endangerment Finding on Greenhouse Gases

The scientific community, the business community and the policy world have spent decades studying greenhouse gas pollution and climate change. Scientists in the U.S. and around the world have tracked in the last century - and in particular the last three decades - alarming increases in the amount of greenhouse gases in our skies. That increase is deteriorating the natural balance in our atmosphere and changing our climate.

There have and continue to be debates about how and how quickly climate change will happen if we fail to act. But the overwhelming amounts of scientific study show that the threat is real - as does the evidence before our very eyes. Polar ice caps crumbling into the oceans, changing migratory patterns of animals and broader ranges for deadly diseases, historic droughts, more powerful storms, and disappearing coastlines.

After decades of this mounting evidence, climate change has now become a household issue. Parents across the United States and around the world are concerned for their children and grandchildren. Governments are investing billions in adaptation strategies. Businesses are investing billions in efforts to reduce carbon emissions. Military planners are projecting new hotspots of instability and conflict. They know that if we do not act to reduce greenhouse gases, the planet we leave to the next generation will be a very different place than the one we know today.

In 2007, the U.S. Supreme Court handed down perhaps the most significant decision ever reached in environmental law. The Court ruled that the Clean Air Act, the landmark 1970 law aimed at protecting our air, is written to include greenhouse gas pollution. That verdict echoed what many scientists, policymakers, and concerned citizens have said for years: there are no more excuses for delay.

Regrettably, there was continued delay. But this administration will not ignore science or the law any longer, nor will we avoid the responsibility we owe to our children and grandchildren. Today, I'm proud to announce that EPA has finalized its endangerment finding on greenhouse gas pollution, and is now authorized and obligated to take reasonable efforts to reduce greenhouse pollutants under the Clean Air Act.

This long-overdue finding cements 2009's place in history as the year when the United States Government began seriously addressing the challenge of greenhouse gas pollution and seizing the opportunity of clean-energy reform. In less than 11 months, we have done more to promote clean energy and prevent climate change than happened in the last eight years.

Earlier this year, EPA established this country's first - and what I believe will be a world-leading - nationwide greenhouse gas emissions reporting system. Next month, large emitters in the U.S. will begin working with EPA to monitor their emissions. Beginning in 2011, large emitters will - for the first time - submit publicly available information that will allow us to meaningfully track greenhouse gas emissions over time. This reporting will also bring to light opportunities to jump-start private investment in energy efficiency and new technologies and products - saving money, improving bottom lines and growing the economy. And it does all this in a common-sense way - without putting a burden on small businesses or other critical sectors of our economy.

Through the Recovery Act and the support of strong clean energy reform legislation, President Obama has led the way in cutting greenhouse pollution and reducing our dangerous dependence on foreign oil - which threatens our national security and our economy.

Today's endangerment finding provides the legal foundation for finalizing the recently proposed clean cars program. That program was developed in collaboration with the American auto industry and other stakeholders, and contains the nation's first ever limits on greenhouse gas emissions from American vehicles.

And starting next spring, large emitting facilities will be required to incorporate the best available methods for controlling greenhouse gas emissions when they plan to construct or expand.

These are reasonable, common-sense steps that will allow us to do what the Clean Air Act does best - reduce emissions for better health, drive technology innovation for a better economy, and protect the environment for a better future - all without placing an undue burden on the businesses that make up the better part of our economy.

Today's announcement and these other efforts are designed to complement comprehensive clean energy reform. We look forward to working with Congress to get a bill to the President's desk - and to implementing that bill once it has been signed.

We know that skeptics have and will continue to try to sow doubts about the science. It's no wonder that many people are confused. But raising doubts - even in the face of overwhelming evidence - is a tactic that has been used by defenders of the status quo for years. Those tactics have only served to delay and distract from the real work ahead, namely, growing our clean energy economy and freeing ourselves from foreign oil that endangers our security and our economy.

It's time that we let the science speak for itself. In making this finding, we relied on decades of sound, peer-reviewed, extensively evaluated scientific data. That data came from around the world and from our own U.S. scientists.

Today's action is a step towards enduring, pragmatic solutions to the enormous challenge of climate change. It is a step towards innovation, investment and implementation of technologies that reduce harmful emissions. And it's a step towards green jobs, reduced dependence on foreign oil, and a better future for our children.

It also means that we arrive at the climate talks in Copenhagen with a clear demonstration of our commitment to facing this global challenge. We hope that today's announcement serves as another incentive for far-reaching accords in our meetings this week.

In taking action now and recognizing this threat, we join the hundreds of other countries, thousands of leading scientists, tens of thousands of innovators, entrepreneurs and private companies, millions of Americans and billions of global citizens who have seen the overwhelming evidence and called for action on climate change.

U.S. Climate change