More investors are putting a price on climate change and the environment in a bid to promote a cleaner world.
Green funds look at a company's environmental performance or the products they make before investing in them.
Some economists talk about moving towards a low-carbon economy. They are describing an economy where companies have to operate more cleanly or face big fines for polluting.
More efficient cars, cleaner factories and renewable sources of energy are all part of a low-carbon economy.
Investors want to buy shares in companies that make the best electric cars and best wind turbines.
Jeremy Higgs is the managing director of Environmental Investment Services Asia, the first Hong Kong money manager to focus only on environmental issues. He buys shares in companies involved in the environmental sector and development of low-carbon economies.
He also sells shares of companies that could be financially hurt by their poor environmental record.
'In years to come, these companies that pollute will be hurt by the market. It's not happening so much today, but it will,' Higgs said.
'I'm investing based on my belief in low-carbon economic growth.'
Green funds are a relatively new thing because these companies are still adjusting to new rules that force them to pay more attention to the environment. That means we don't know who the leaders will be yet.
Green funds are good because they make companies think about climate change, the environment and pollution in financial terms.
Green funds help us as consumers send the message to companies that we want a cleaner world.
Cameron is available to speak to primary and secondary students about environmental and climate change issues as well as his recent Arctic sailing expedition. Contact firstname.lastname@example.org