The Globe and Mail reports in its Saturday edition that last summer, Bill Gates huddled in London with representatives of some of the world's wealthiest people, including Amazon founder Jeff Bezos, SoftBank founder Masayoshi Son and Prince al-Waleed bin Talal of Saudi Arabia. Guest columnists David Gelles and Christopher Flavelle write they were evaluating their joint investments in companies that could help the world combat climate change. Among the businesses in their portfolio, four stood out as having a particularly audacious goal: They were working to strip carbon dioxide from the atmosphere, for a profit. As countries around the world continue to pump planet-warming pollution into the skies, driving global temperatures to record levels, the financial world is racing to support the emerging field of carbon-dioxide removal, seeking both an environmental miracle and a financial windfall. "It's the single greatest opportunity I've seen in 20 years of doing venture capital," said Damien Steel, chief executive officer of Canada's Deep Sky, which has raised more than $50-million (U.S.) to develop carbon-dioxide removal projects. This year, Microsoft, Google and British Airways committed to purchase carbon removal credits.