Rajendra Pachauri, U.N. climate scientist, has good news and bad news. I'll give you the latter first: eat less meat. Doing so will help slow global warming. The good news, also related to climate change, is that Pachauri, chairman of the Intergovernmental Panel on Climate Change for the United Nations, investing in green technologies now is a smart move. So, by following Pachauri's advice, you cut down on your meat but reward yourself with a decent investment return.

If you take his advice as a whole (pretending you don't know you can do one part without the other), it's like getting paid to eat your veggies. Everyone who's been five years old at some point knows that being given green to eat green is ample motivation. The fun part, here, is that you're financing it by investing in green. It all matches!

We're still in the early stages of this trend, but it's pretty clear that the green energy sector is fast becoming a venture capital darling. Today, for example, five deals were announced in one publication alone (three VC, two acquisitions). The three investments account for $47.4 million in VC investment. And only yesterday, Solazyme picked up another $57 million in its Series C round.

In what remains a capital-constrained market, the cash is still flowing. In the private equity space, investments in clean technologies have remained steady from 2007 to 2008, despite broader economic calamity. Such commitment this early in the game may hint at what the next bubble will be.

Investments in clean energy projects and companies reached $155 billion last year, surpassing fossil fuel investments. According to a United Nations report, $13.5 billion in new private investment was directed to companies that are developing new technologies, with almost half that (according to Private Equity Intelligence, Ltd.) coming from clean technology-focused private equity funds.

Clean energy sources account for the majority of energy investments last year, with $105 billion spent on developing 40GW of wind, solar, small hydro, biomass and geothermal energy generation capabilities. Large hydro (25GW) accounted for another $35 billion in investments.

Totaling $140 billion, this accounts for 56% of investments in power last year. The aggregate 65GW, however, represents only 41% of new capacity developed in 2008. Renewable energy dominated the clean technology space, 75% of the total at $117 billion.

Investments in clean energy technology grew 5% from 2007 to 2008, leading to a second consecutive record-setting year. Emerging markets made the difference last year – particularly China and Brazil. China has become the second largest wind market in the worlds (as measured by new capacity) and the world's top photovoltaic manufacturer.

Geothermal appears to be on the horizon for several countries, including Australia and Kenya. Nonetheless, the ongoing financial crisis has put the squeeze on the clean energy space. U.S. investments fell 2%, and growth slowed considerably in Europe.

Despite all their talk about ethanol and hydrogen, American car companies are way behind in the race to create reduced emission vehicles.

The American Council for an Energy-Efficient Economy recently released its list of the greenest cars for 2008, and it's dominated by Japanese producers. The list of 12 greenest cars, which is slanted toward hybrids, includes four Hondas (NYSE: HMC) and four Toyotas (NYSE: TM). Ford (NYSE: F) made the list with its Focus hybrid, while General Motors (NYSE: GM) failed to place in the top 12, although its Chevrolet Tahoe hybrid was cited by the group for 'scoring well.'

The good news, if there is any, is that Detroit is not alone in failing to create cleaner cars. The Council also released a Meanest Vehicles for the Environment list which is dominated by German cars, including three Mercedes diesels. But three American vehicles also made the list, including the GMC Yukon and the Hummer H2.

The problem goes way beyond matters of national pride. Green technology is an increasingly important asset for global producers, and it's obvious that Detroit is still far behind in this important area of competition. Worse, it's not clear how serious the Big Three are about catching up. When someone like GM Vice Chairman and noted American car nut Bob Lutz dismisses global warming as a "crock," you have wonder how much effort is going into new technology -- as opposed to simply talking about new technology that is always just around the corner but never on the showroom floor.