The world continues to warm. In the geological context, it is warming very rapidly. Likely more rapidly than at any time in at least the past 200 million years. And as long as this very swift warming trend continues, as long as it is not bent back, it spells serious trouble for the world’s weather, for stable coastlines, for corals, for ocean health, for stable growing seasons and for so, so many more things that we all depend on.

2017 was the second hottest year in the global climate record. It was notable due to the fact that it followed the strong El Nino year of 2016 with ENSO neutral trending toward La Nina conditions. The short term conditions that emerged during 2017 would tend to variably cool the Earth. But the resulting cool-down from 2016 to 2017 was marginal at best — representing about half the counter-trend drop-off following the strong 1998 El Nino. Instead, much warmer than normal polar zones kept the world in record hot ranges even as the Equator tried, but failed, to significantly cool.

(Rate of global warming since the 2010s appears to have accelerated in the above graph following a strong El Nino during 2015-2016 and a very mild counter-trend cooling during 2017. Temperatures in 2018 are likely to be similar to those seen during 2017 if the present prediction for ENSO-Neutral conditions is born out. Image source: NASA.)

Overall, warming above historical baselines remains quite acute in the NASA graph. And global temperatures for 2017 were 1.12 C warmer than 1880s averages. This is comparable to the 1 to 2 C warmer than Holocene range last seen during the Eemian — when oceans were about 20 to 30 feet higher than they were during the 20th Century.

Present rate of warming appears to be at the higher end of the observed 0.15 to 0.20 C warming per decade increase since the mid 1970s. This rate of warming is approximately 30 to 50 times faster than the warming that ended the last ice age. During that time, it took ten thousand years for the Earth to warm by about 4 degrees Celsius. Now we are at risk of seeing a similar warming within 1 to 2 Centuries or less if a switch back to business as usual fossil fuel burning occurs.

(This is what a world featuring temperatures hotter than 1 C above late 19th Century averages looks like. All-in-all not a very cool place. If present levels of atmospheric greenhouse gasses simply remain and do not rise, we are likely to see 2 to 3 times this level of warming long-term and over the course of multiple centuries. Present policy pathways for additional greenhouse gas emissions will likely achieve 2-3 C warming or more by the end of this Century unless more rapid energy transitions, carbon emission curtailment, and atmospheric carbon capture are undertaken. Image source: NASA.)

NASA and other top scientific agencies point toward human CO2 and other greenhouse gas emissions as the primary cause of present warming and a related growing disruption to the Earth’s climate system. Action to switch energy systems away from fossil fuels and to, as a follow-on, draw down a portion of that climate warming CO2 now in the atmosphere is presently necessary to prevent ratcheting levels of harm and disruption on local, regional and global scales.

Though mild compared to the potential impacts of future human-forced warming, present warming and presently elevated CO2 levels in the range of 407 ppm and 492 ppm CO2e are enough to generate climate disruptions of serious consequence over the short, medium and long term that negatively impact the health of human civilizations and the natural world. Meanwhile, continued fossil fuel burning and related dumping of carbon into the atmosphere is increasing the risk of catastrophic events and related mass loss of human shelter, forests, fertile growing zones, and earth system life support services. The need for response and a rapid energy transition to renewables is therefore both considerable and growing.