to be the generation that fiddled while the planet burned. and as the u.n. advocates for urgency, there are nations such as zimbabwe which are already feeling the effects of climate change. here's cnn's david mckenzie. >> it's incredible, isn't it? the victoria falls. one of the natural wonders of the world. but -- and it's a big but -- this entire stretch of rock should be churning with white water. climate scientists say that the climate crisis is hemorrhaging this region. a multi-year drought has transformed zimbabwe's rivers and farmland into miles upon miles of sand and scorched earth. here they don't speculate about climate change, they're suffering because of it. once proud productive farmers like this man reduced to handouts to survive. reduced to just one meal a day.