As the world continues to reel from ongoing heat waves, flooding and wildfires, a new report from the United Nations said climate change has been "unequivocally" caused by human activity – and warned that some damage already done is "irreversible." The UN released its Intergovernmental Panel on Climate Change (IPCC) report, the most comprehensive report from the group since 2013. The summary included a series of stark statistics that laid out just how climate change has affected the planet over the last few centuries, including the fact that global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2,000 years. And since 2011, greenhouse gas concentrations have continued to rise, and each of the last four decades has been successively warmer than any decade that preceded it since 1850, according to the report. Such a rise in temperature has caused a multitude of effects, including heat waves, heavy precipitation, droughts and tropical cyclones. The report laid out five different scenarios for the future, each one based on how much carbon emissions are cut. Under every single scenario, global surface temperatures will still continue to increase until at least the mid-century – and in the worst-case scenario, the end of the century could find the world 3.3 degrees Celsius hotter than it is now. Despite that, report co-author and climate scientist Zeke Hausfather told the AP that hitting 3.3 degrees is unlikely. While UN Secretary-General António Guterres called the findings a "code red for humanity," he said he still has hope that world leaders can prevent 1.5 degrees of warming.