Investing in climate change used to mean putting money into efforts to stop global warming. Morgan Stanley, Goldman Sachs, and other firms took stakes in wind farms and tidal-energy projects, and set up carbon-trading desks. The appeal of cleantech has dimmed as efforts to curb greenhouse gas emissions have faltered: Venture capital and private equity investments fell 34 percent last year, to $5.8 billion, according to Bloomberg New Energy Finance.
