Sobering Climate Risks / Note on Emerging Science: Hot Potato Blues / Beyond the Headlines / Exploring the Parks: Cactus and Snow in the Desert Sky Islands / BirdNote®: Ponderosa Pine Savanna / Horizon by Barry Lopez If carbon emissions keep going up until 2030 it will be too late to avoid a 'hot house' Earth with a billion climate refugees starting in 2050, according to the Australia-based Breakthrough National Centre for Climate Restoration. These researchers warn the climate is changing faster than politicians and the public are responding, and say interventions on a scale never before seen during peacetime are needed right now. Also, Coronado National Forest, north of Tucson, Arizona is the latest subject of Living on Earth's occasional series on America's public lands. There's plenty of heat and cacti, of course - but also many species that you're more likely to find far north of the desert Southwest, and even enough snow for skiing! We take a trip to the remarkably diverse biomes of Arizona's Sky Islands, with a local biologist as our guide. And in his new book Horizon, 30 years in the making, award-winning writer Barry Lopez asks: "Who is our navigator?" now, in this time of climate change and pervasive inequality. Looking towards the horizon and more, in this episode of Living on Earth from PRI. Learn more about your ad choices. Visit megaphone.fm/adchoices