Nasa says it is possible statistically to remove the natural warming and cooling effects that come from El Niño and La Niña. When this smoothing is done (red line), 2017 comes out warmer than any previous year. The grey columns denote major volcanic eruptions that ordinarily depress the warming trend.
Excerpts:
The World Meteorological Organization Secretary-General Petteri Taalas said the long-term temperature trend was far more important than the ranking of individual years.
“Arctic warmth has been especially pronounced and this will have profound and long-lasting repercussions on sea levels, and on weather patterns in other parts of the world.”
Prof Richard Allan from the University of Reading said: “Rather than warming being inconsequential or catastrophic, as some have suggested, we can be sure societies are facing a dangerous temperature rise, but one which we still have time to fix.
“The conclusions confirm that human-caused climate change is a serious concern.
“But if we act now with sustained and substantial cuts in greenhouse gas emissions, societies will still be able to avoid much of the most dangerous climate change predicted by computer simulations.”