Business Green: Global optimism that climate change can be tackled has fallen markedly over the past three years, although future “mega-polluters” such as China and India are among those most confident that solutions can be developed. That is the conclusion of the fourth annual HSBC Climate Confidence Monitor, published yesterday, which reveals that climate change remains one of the top three global concerns, along with economic stability and terrorism. The survey of about 15,000 people revealed that those…