By Steven Duke
Editor, One Planet
Achim Steiner is executive director of the UN Environment Programme
The UN's head of environment has been left "stunned" by the billions of dollars pumped into ailing companies following the global financial crisis.
Achim Steiner told the BBC One Planet programme that he had fought for years to secure much smaller sums to tackle poverty and climate change.
"We waited perhaps a decade to get $5bn ($3.3bn) to accelerate development of renewable energy," he said.
We now see $20bn (£13.3bn) paid [to] a car company simply to keep it alive."
He said he was surprised that such huge amounts had "suddenly been found" to tackle the crisis.
Vast sums of money have been spent on bank bailouts in the UK and the US alone.
Billions more has been promised in aid for struggling industries, such as automotive manufacturers.
But Mr Steiner, who is based in the Kenyan capital of Nairobi, warned we are passing the bill to the next generation, and stressed that if extra investment is not found to tackle climate change, the bail-outs would be "a terrible waste of money".
Despite the urgency of governments to ensure financial institutions do not collapse, Mr Steiner urged the public not to be "sold the false story" of banks having to be fixed before worrying about other issues such as environmental protection.
If that did happen, Mr Steiner believes it would represent "the greatest political tragedy of the last five decades".
In the interview, the Brazilian-born UN director also suggested the world's richest countries could make huge inroads to tackling climate change by adding $5 (£3.30) to the cost of a barrel of oil - which he estimates would raise over $100bn (£66.5bn) to invest in new technology.
"Are you really that worried about paying three cents more per litre of oil in order to reverse global warming - what would be the debate if we put it in those terms?"
But when asked which governments he thought would be prepared to put such a surcharge on oil, Mr Steiner admitted, "Not a single one, right now".
The full interview with Achim Steiner can be heard on the 7 May edition of the One Planet programme on the BBC World Service.