Guardian: “Climate change has already left its mark “on all continents and across the oceans“, damaging food crops, spreading disease, and melting glaciers, according to the leaked text of a blockbuster UN climate science report due out on Monday. Government officials and scientists are gathered in Yokohama this week to wrangle over every line of a summary of the report before the final wording is released on Monday – the first update in seven years. Nearly 500 people must sign off on the exact wording of the summary, including the 66 expert authors, 271 officials from 115 countries, and 57 observers. But governments have already signed off on the critical finding that climate change is already having an effect, and that even a small amount of warming in the future could lead to “abrupt and irreversible changes”, according to documents seen by the Guardian. “In recent decades, changes in climate have caused impacts on natural and human systems on all continents and across the oceans,” the final report from the Intergovernmental Panel on Climate Change will say. Some parts of the world could soon be at a tipping point. For others, that tipping point has already arrived. “Both warm water coral reef and Arctic ecosystems are already experiencing irreversible regime shifts,” the approved version of the report will say. This will be the second of three reports on the causes, consequences of and solutions to climate change, drawing on researchers from around the world. The first report, released last September in Stockholm, found humans were the “dominant cause” of climate change, and warned that much of the world’s fossil fuel reserves would have to stay in the ground to avoid catastrophic climate change. This report will, for the first time, look at the effects of climate change as a series of risks – with those risks multiplying as temperatures warm.”