Scientists are testing new technologies they hope could counteract the effects of climate change. But how could that work on a global scale? And - if it is possible at all - what are the dangers? Global climate change is now a major existential threat for the entire planet. Despite this, the Trump administration chose to withdraw from the Paris climate accord. The world’s second-largest emitter of greenhouse gases thus became the first nation to abandon the global effort to fight climate change. Global emissions of carbon dioxide reach record high levels, year after year. Polar ice is melting and sea levels are rising. What’s more, a Washington Post analysis suggests roughly one-tenth of the globe has already warmed by more than two degrees Celsius. Researchers say we may soon have no choice but to use geoengineering to cool down the climate. Perhaps ironically, most of the research is carried out in the US - one of the greatest climate offenders.