“Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. Scientists are also observing changes across the whole of Earth’s climate system; in the atmosphere, in the oceans, ice floes, and on land. Many of these changes are unprecedented, and some of the shifts are in motion now, while some – such as continued sea level rise – are already ‘irreversible’ for centuries to millennia, ahead, the report warns. But there is still time to limit climate change, IPCC experts say. Strong and sustained reductions in emissions of carbon dioxide (CO2) and other greenhouse gases, could quickly make air quality better, and in 20 to 30 years global temperatures could stabilize. ‘Code red for humanity’. The UN Secretary-General António Guterres said the Working Group’s report was nothing less than “a code red for humanity. The alarm bells are deafening, and the evidence is irrefutable”. He noted that the internationally-agreed threshold of 1.5 degrees above pre-industrial levels of global heating was “perilously close. We are at imminent risk of hitting 1.5 degrees in the near term. The only way to prevent exceeding this threshold, is by urgently stepping up our efforts, and persuing the most ambitious path.”