As rising floodwaters assault Venice, there’s now an 85% chance that 2019 will come in as second warmest year
Two U.S. agencies have now released their global warming report cards for last month, and they both show the same depressing grade:
Of the 139 Octobers since 1880, last month was the second warmest on record.
A third analysis, from the Copernicus program of the European Union, rated the month as warmest October on record.
The news of global warming’s strengthening grip comes as 70 percent of the city of Venice was submerged by catastrophic flooding, brought about in part by rising sea levels. Venice offers a glimpse of what coastal cities worldwide are facing as melting ice sheets and warming ocean waters cause the seas to come up even more.
By NASA’s reckoning, October was 1.87 degrees warmer than the 1951-1980 average. The National Oceanic and Atmospheric Administration independently found a global temperature anomaly of 1.76°F above the 20th century average.
The trivial variations in the numbers from the different scientific agencies arise from their independent evaluations. And despite these differences, they agree on the big picture: As carbon dioxide and other heat-trapping greenhouse gases have continued to accumulate in the atmosphere due to human activities, Earth has been warming.
As the blue line in the graph above illustrates, global temperatures haven’t been on a straight, unvarying upward march. Year by year, nature does bring some dips along with some spikes. But decade-by-decade, the upward trend couldn’t be clearer — and the rate of warming even appears to be increasing.
Looking ahead to the end of the year, 2019 as a whole stands an 85 percent chance of coming in as second warmest year on record, according to Gavin Schmidt, director of NASA’s climate analysis efforts. This year is trailing only 2016, which saw significant warming from a super El Nino.
In fact, the 10 warmest Octobers have all occurred since 2003 — and the five warmest have all occurred since 2015, according to NOAA.
“October 2019 also marks the 43rd consecutive October and the 418th consecutive month with temperatures, at least nominally, above the 20th century average,” NOAA’s report finds.
The map above portrays the same temperature anomaly data as the one at the top of this post. It just does it in a way that emphasizes temperature differences a bit more clearly.
I decided to include it here because it draws attention to the dramatic cold spot covering much of North America. According to NOAA, temperatures in this region were 2.7°F below average, or even cooler, during October.
Since the early 1950s, Octobers have been getting steadily warmer in most parts of the world. But that fairly big chunk of North America has been a glaring exception: It has cooled somewhat. (This is not true for September or November.)
The “noise” of natural variability is likely a prime cause, according to the monthly global temperature report from Columbia University’s Climate Science, Awareness and Solutions group. “However, as has been much discussed, the weaker jet stream associated with polar warming allows blasts of Arctic air to reach midlatitudes more readily,” the update also notes.
In this way, human-caused warming — which has been twice as intense in the Arctic as anywhere else on Earth — may be a significant contributor to that strange October cold spot over much of North America.