According to NASA’s global monitoring division, the period of December 2017 through November 2018 was the fourth hottest such time ever measured in the global climate record. Starting in 1880, the measure now spans 138 years. And it marks a period of unprecedented rapid change in the Earth’s climate system — driven primarily by fossil fuel burning and the resulting emission of heat trapping gasses into the Earth’s atmosphere.

(The above graphic provided by NASA GISS shows the ongoing monthly warming trend since 1880. Recent record hot years show up in red. Present 2018 dates and temperatures are indicated by the black dots and red line near the top of the graph. Image source: NASA.)

NASA’s monitor shows 2018 hitting 0.82 degrees Celsius above its own mid 20th Century baseline for the 12 month time-frame. This puts 2018 about 1.04 C above 1880s averages in the December to November period composing NASA’s climate year. 2018 is now on track to be the fourth hottest year behind 2016 (#1), 2017 (#2), and 2015 (#3). As a result, every year of the past four years represents the hottest years ever recorded since consistent measurements began more than a century ago.

According to every major climate monitoring agency, the uncontested driver of this warming trend is an ongoing and growing fossil fuel based greenhouse gas emission. During 2018, atmospheric carbon dioxide levels rose to an average near 410 parts per million and carbon dioxide equivalents, a measure taking into account all greenhouse gasses, hit near 495 parts per million. This level of heat trapping gasses is unprecedented for at least the past 18 million years and will result in significant continued warming if they remain or keep rising.

Looking forward, an emerging El Nino combined with these high and rising levels of heat trapping gasses has the potential to produce record global temperatures during 2019. According to NOAA, sea surface temperatures in the Equatorial Pacific are presently in the El Nino range and the climate monitor is predicting a 90 percent chance of official El Nino formation during the winter of 2018 with a 60 percent chance for its continuance during spring.

(Video blog providing in-depth analysis of NASA’s most recent global temperature update.)

El Nino is the hot end of the natural variability scale. When combined with rising atmospheric greenhouse gasses trapping more heat in the Earth system, it has tended to produce record hot or near record hot years. 2016 saw a very strong El Nino along with a major new global temperature milestone in the range of 1.21 C above 1880s averages. Though the 2019 El Nino is predicted to be milder than the 2016 event, high and rising greenhouse gasses means that a new record could be breached with temperatures likely to hit a range between 1.17 C and 1.3 C.

With present temperatures now well outside the typical range for the past 10,000 years following the last ice age, each additional 0.1 C of warming is likely to bring additional impacts on top of the more severe weather, worsening fires, rising seas, and ocean health impacts we have already seen. It is thus the case that the age of human caused climate change is upon us and that escalating climate action is needed to prevent a quick ramp to catastrophic events.