Immediate steps needed to mitigate climate change impact: Obama

US President Barack Obama said on Wednesday that climate change "can no longer be denied" and immediate measures are needed to mitigate its effects.

Obama said during his Earth Day address on Wednesday at the Everglades National Park -- the largest subtropical wilderness in the US -- that global warming threatened the 600,000-hectare (1.5-million-acre) park and the communities that depended on it, posing a risk to the $82 billion tourist industry of the state of Florida, according to the Spanish news agency Efe.

Obama said climate change was a problem that could not be left for future generations to address and urged the US Congress to approve new funds for environmental protection.

"This is a problem now. It has serious implications for the way we live right now. Stronger storms. Deeper droughts. Longer wildfire seasons," Obama said, adding that the Pentagon also viewed climate change as posing an "increasing set of risks to our national security".

The US president said that $2.2 billion had already been spent on restoration efforts in the Everglades and that this year he had proposed an additional $240 million for that South Florida wetland system to restore its natural water flow. Obama noted that the wetland system was "one of the best defences against climate change and rising sea levels".

The president also announced $25 million in public and private funding for restoration projects at the US national parks, making a note of a recent report that "every dollar invested in the National Park Service generates $10 for the economy."

Obama said climate change was "not some impossible problem that we cannot solve" and noted that five years ago local Republicans and Democrats formed the Southeast Florida Regional Climate Change Compact -- "an agreement to work together to fight climate change" that has become a "model not just for the country but for the world".

But despite Obama's appeals to bipartisanship, the White House said Florida Governor Rick Scott, a Republican who had repeatedly said that he was not convinced by the science of climate change, declined a formal invitation to attend Obama's speech.

"Simply refusing to say the words 'climate change' doesn't mean that climate change isn't happening. If you've got a coming storm, you don't stick your head in the sand; you prepare for the storm. You make sure our communities are prepared for climate change. And that's an economic imperative," Obama said.