March 2018 was the fifth warmest March since 1880, according to NOAA’s Global Climate Report.
With La Niña waning, temperatures have stabilized at the long-term trend (upward). As the first serious results of global warming become evident, climate negotiators prepare for their December meeting to resolve disputes remaining from the Paris Agreement. Let’s check it all out.
March Average Global Temperature Is 0.83 C (1.50 F) Above Average
Though March was only fifth warmest overall, new records were set in many places. Most noticeable was the warmth in southern oceans — Atlantic, Pacific, and Indian — all three of which had large areas of record temperatures.
Over land areas, a good chunk of China and a swath from Egypt northeastward through the Middle East set warm records. As usual, no place reported record cold. It is clear that La Niña had a cooling effect that bled into the adjacent parts of the South Pacific so that despite the warm records at higher latitudes, the southern hemisphere ocean was only ninth warmest ever for March.
Is La Niña Over?
La Niña is over as a practical matter, but not officially. That’s because the formal definition averages temperatures over three-month periods. Though the water temperature in the mid-Pacific has warmed above the critical threshold of 0.5 C below normal, the three-month period from February to April will still show an average temperature lower than the threshold.
This has been an unusually mild La Niña judging by those following strong El Niño events in the past. Many forecasts indicate a return to El Niño conditions by fall, though the accuracy of forecasts for post-La Niña years has historically been low.
Unusual Weather Can Be An Indication Of Climate Change
The weather sets new records all the time. But when occurrences of extreme weather are as frequent — or as extreme — as they have been recently, it’s time to consider if the problem is global warming. Last summer, we had the devastating hurricanes; this winter, we had four major nor’easters in one month on the US east coast. And now…..
Last week, Kawaii, the northernmost island in the Hawaiian chain, recorded three feet of rain in two days. This Texas-sized, Harveyesque total was only the biggest in 25 years — but there’s a reason it should be taken very seriously.
The rains of 25 years ago were caused by Hurricane Iniki, which veered north in its trek across the Pacific. That is to be expected occasionally, probably more often now with the ocean warming. But the recent event was not from a tropical cyclone, though the source of the moisture was the tropical ocean. The moisture was pulled north by a swirl in the jet stream at an unusually low latitude.
Farther north, the city of Erie, Pennsylvania broke its all-time winter snowfall record — by a lot. The new record is 198 inches; the former record was 149 inches. This time, the culprit was a curl in the jet stream that wouldn’t move.
Bottom line: Many meteorologists believe they see a qualitative change in the jet stream, though no one has yet quantified it.
Water Temperatures Continue To Show Latitudinal Correlation
This column has pointed out recently that water temperatures have been above normal around 40 degrees and below normal near 20 degrees latitude in both hemispheres.
The trend continues in the latest water temperature anomaly analysis. And there is something else of note: Cold water lies adjacent to Antarctica, Greenland, and Alaska. This cold water is a result of melting glaciers and has a negative feedback effect on global warming.
This seems counterintuitive, but the meltwater is fresh, and fresh water is less dense than salt, so it floats, even when it’s cold.
Will Politicians Step Up?
The Paris Climate Agreement, hammered out in 2015 and subsequently ratified by 195 countries, left much TBD (to be decided). The agreed goal was to limit the global rise in temperature to 2 C. But the mechanism for accomplishing this has never been clear. Countries are only obligated to present an INDC (intended nationally determined contribution). So far, the INDCs, by accepted analysis, will only keep the rise in temperature to 2.7 C. And the INDCs are just promises. A cynic would say ‘Who’s gonna make them keep the promises?’
Recognizing that the initial INDCs were unlikely to accomplish the stated goal, the representatives of the various nations provided for future meetings at which the countries would ‘set more ambitious targets.’ Again, the cynic would say, ‘Yeah, right.’
I’m willing to view the glass and make the call when I see who drinks. The historic agreement involving virtually every nation certainly fills the glass half way; but the usual rancor over who sacrifices and who has rights to do what could drain the glass, while action subsequent to a realization of the danger could fill it up.
Difficult negotiations loom, as representatives at COP24, scheduled to begin December 3, 2018, try to decide who pays for developing countries to skip the fossil fuel stage of energy production, a major point of contention.
The next Climate Change Checkup will be published after the release of NOAA’s April Global Climate Report (around May 18).
The next Weather Around The World will be published on May 1, 2018.