The relentless warming of the earth’s atmosphere and ocean took a sidestep in April — it was only the fourth warmest in 135 years of record-keeping.
Some trends stayed in place, while others reversed. Looked at from a more informative 12-month perspective, the period May, 2014 to April, 2015 tied the record set a month before.
As has been the case for several months, the warming was driven by increasing sea temperatures — a new record for April — while land temperatures temporarily leveled off.
With an increasing chance of El Niño Eggplant strengthening and lasting through the summer, sea temperatures will probably continue to rise.
April Land And Sea Temperature Anomalies
The following are some of the highlights of the temperature anomalies for April:
- Global air and sea temperatures averaged 1.33 degrees Fahrenheit above the 20th century average. The land was exactly two degrees above average; oceans were 1.08 degrees above average.
- It was the warmest April on record in parts of Cuba, Mexico, Brazil, and Tanzania.
- The greatest departure from normal, over nine degrees, was in north-central Russia, though this was not a record.
- Following its eighth warmest March, Australia reported its 22nd coldest April in the 106-year period of record.
- On the ocean, the persistent warm water set a new record in the Gulf of Alaska and the strengthening El Niño was evident in the equatorial Pacific.
- Record cold water was observed in the North Atlantic between Canada and northern Europe.
The Trend Of Temperature On A Yearly Time Scale
When temperatures are averaged over a time span of a year, the statistics begin to look scary. The year May, 2015 to April, 2015 tied the period ending in March, 2015 for the warmest 12-months ever.
The record before that: the year ending in February, 2015.
The record before that: the year ending in January, 2015. I’m sure you get the idea.
Prior to August, 2014, the warmest one-year period was September, 1997 to August, 1998. Now that year is tied for eighth place. It is a significant demotion.
Climate skeptics have long claimed that global warming leveled off after 1997. They always started their measurements with that year, an anomalous one because of a powerful El Nino. Now the current temperatures have surpassed the readings of 1997-8, and the upward trend could not be clearer.
Precipitation not only varies greatly from month to month, it can be highly variable over short distances. However, there are some interesting features of this month’s precipitation anomaly chart.
- In South America, rainfall was less than one-quarter normal in the northern tip and through central Argentina.
- In Africa, drought conditions persist on the edges of the Sahara. No doubt rain gauges in the middle of the desert, if there were any, would have been completely empty.
- Much of Europe was dry.
- The drought continued in California, where the governor announced new water-use restrictions.
- Much above normal rainfall was recorded in the southeast United States, southeast Australia, much of India, and central South America.
Sea Ice Trends Are Unbroken
A puzzling anomaly has emerged in recent years with respect to sea ice extent. The simple interpretation of the data is that the Arctic is melting and the Antarctic is freezing. Sea ice continues to increase in the Antarctic and shrink in the Arctic. Here are the figures for April:
- Antarctic sea ice extent was 22% above the 1981-2019 average, the greatest on record.
- Arctic sea ice extent was 5.5% below average, the second lowest ever recorded for April.
A number of theories have been advanced to explain this conundrum, but none is completely convincing. Decoded Science would like to offer a simple explanation.
Ice reflects solar radiation, while water mainly absorbs it. So, ice extent has a natural feedback mechanism: Once ice starts to melt, more radiation is absorbed, melting more ice. Similarly, once ice increases, more radiation is reflected, the air cools, and more ice forms.
The natural question to ask is: What started the process? With respect to the Arctic, it’s pretty clear that the generally rising land and sea temperatures got it going. But what about the Antarctic?
All we can offer is that possibly a few anomalously cold years set things in motion.
The increase in Antarctic sea ice is certainly not a refutation of global warming. The April global land and sea temperatures make that clear. But it is a signal that climate change will not be spread evenly over the planet.
What Will The May Global Land And Sea Temperatures Be Like?
Following the trend, it’s pretty easy to predict that May will be warm. And with El Niño cranking up, it is very likely that temperatures worldwide will set new records.
Are the politicians paying any attention at all?
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