Investment in renewable energy rose some 60 percent in 2007, according to the UN Environment Programme.

Amid rising oil prices and concerns about global warming, global investors put $148 billion into new wind, solar, and biofuel projects. In 2006, alternative energy drew $92.6 billion. In 2005, that figure was $58.5 billion.

"Just as thousands were drawn to California and the Klondike in the late 1800s, the green energy gold rush is attracting legions of modern day prospectors in all parts of the globe," said UNEP head Achim Steiner in a press release.

"A century later, the key difference is that a higher proportion of those looking for riches today may find them," he said. "With world temperatures and fossil fuel prices climbing higher, it is increasingly obvious to the public and investors alike that the transition to a low-carbon society is both a global imperative and an inevitability....What is unfolding is nothing less than a fundamental transformation of the world's energy infrastructure."

According to UNEP, most of the money went to Europe, where stricter climate change rules are encouraging investment. Second was the United States. China, India, and Brazil saw their portion of new investment increase from 12 percent in 2004 to 22 percent in 2007, an absolute increase from $1.8 billion to $26 billion.

Most of the money went into wind power, even more than what went into nuclear. In Europe, wind power accounted for 40 percent of new alternative energy investment; in the United States it was 30 percent. Private investment in biofuels fell by almost one-third, and much of the money shifted to Brazil, India, and China. Investments in solar power and energy efficiency surged.

UNEP also noted that carbon financing is shifting to the private sector, as carbon trading schemes become more established.

The full report is available here.