Substantial reductions in emissions would require large changes in inv — Scientific consensus on climate change

"(SRM) involves large-scale methods... is untested and is not included in any of the mitigation scenarios. If it were deployed, SRM would entail numerous uncertainties, side effects, risks and shortcomings... If it were terminated [after and if once begun], there is high confidence that surface temperatures would rise very rapidly impacting ecosystems..."

"[A]ssessments that examine only the next 100 years may well underestimate the magnitude of the eventual impacts."

"[R]isk increases with increases in both the rate and the magnitude of climate change."

"It is virtually certain that there will be more frequent hot and fewer cold temperature extremes over most land areas on daily and seasonal timescales, as global mean surface temperature increases."

"Many of the observed changes since the 1950s are unprecedented over decades to millennia."

"There are multiple mitigation pathways that are likely to limit warming to below 2°C relative to pre-industrial levels. These pathways would require substantial emissions reductions over the next few decades and near zero emissions of CO2 and other long-lived greenhouse gases by the end of the century."