Sir Ghillean (Iain) T. Prance, the eminent botanist who served as director of Britain’s Royal Botanic Gardens, Kew, from 1988 to 1999, was in New York this week to receive the Gold Medal of The New York Botanical Garden for his contributions to plant science. The award is given infrequently; the last recipient was Edward O. Wilson, in 2002.

Sir Ghillean has done research across the world, including the Amazon, where he has witnessed dramatic changes over 40 years. “I went to Suriname in 1963 and Brazil in 1964, and there was very little damage to the rainforest,” he told me. “But by the 70s they had built a highway across the Amazon, then colonization followed, with cattle ranching in the 1980s and now soybean farming. We’ve lost 23% of the Brazilian Amazon rainforest, but there is still a lot to fight for.”

I asked him what we’ve learned about what works to preserve rainforest and what doesn’t. “Sustainable forestry on the whole hasn’t lived up to its promise,” he said. “Sustainable use is possible, but less than 1% of development in the Amazon is truly sustainable.” The only real hope he sees is for wealthy nations to step up and pay nations with significant remaining rainforest to keep it intact, something Guyana has asked the world to do for its rainforest, as I blogged about last May.

He is pessimistic about how the environment will fare in a global recession, warning that “a global economic downturn will be disastrous for the environment. It costs money to preserve rainforest, and when you have people to feed countries make that [basic human needs] their priority.” Here’s my question: how come we didn’t do more when the world was flush with cash?