LONDON - Global revenues from climate-related businesses such as energy efficiency rose by 75 percent in 2008 to $530 billion and could exceed $2 trillion by 2020, HSBC Global Research estimated on Friday.

In the 2006 Stern Review on the economics of climate change, climate-related revenues were forecast to climb to $500 billion by 2050.

We can see that this seemingly huge figure has already been surpassed well ahead of time as more and more businesses adapt their business model, said Joaquim de Lima, global head of quant research for equities at HSBC.

The climate sector has surpassed the size of the global aerospace or defense industry, with the United States, Japan, France, Germany and Spain accounting for 76 percent of global climate revenues, the report found.

For revenues to rise to $2 trillion, the way energy is generated and used needs to change and continued government support is needed.

The four core investment pillars will be low-carbon energy production, energy efficiency, control of water, waste and pollution and climate finance, the report said.

Energy efficiency recorded the highest investment returns in the year to date at 30 percent, followed by carbon finance at 24 percent.

This is a very significant trend given the substantial share of climate stimulus funds that have been directed at energy efficiency and energy management by governments across the globe, HSBC analysts said.

(Reporting by Nina Chestney; Editing by Anthony Barker)