NOAA has published its global air and sea temperatures for February of 2015. It was the second warmest February in the 135 years since atmospheric scientists began keeping records, following the second warmest January.
But, lest climate-change-deniers jump on this as evidence that global warming is leveling off, the data should be taken in longer-term historical context.
Together, January and February was the warmest such period ever, as was the Northern Hemisphere’s winter (December, January, and February), and the most recent calendar year (March, 2014 through February, 2015).
In fact any period ending with February and longer than a month is warmer than any preceding comparable period.
For the second consecutive month, the air temperature was second warmest and the sea surface temperature (SST) was the third warmest. This follows several months of soaring SSTs and stagnant air temperatures. Though the average departure was about a degree and a half above the long-term average for combined land and sea temperatures, several large departures (both positive and negative) are conspicuous. Here are some of the highlights:
- Cold temperature departures of more than five degrees in the eastern United States stand out in dark blue on the map in contrast to the warm temperatures (red) almost everywhere else.
- Much of the US west of the Rocky Mountains had temperatures more than five degrees above normal.
- Very warm temperatures — as much as ten degrees above average — stretched across northern Europe and northern Russia.
- Australia was very warm — the second warmest February on record.
- The warm water anomaly in the Gulf of Alaska continued. Temperatures in Alaska followed suit.
- The SST in the central Pacific Ocean continues to be somewhat above normal — a weak El Niño condition.
- Large parts of Africa, Asia, the Middle East, and South America were well above average.
- Spain and adjacent northern Africa bucked the global trend by recording below average temperatures.
The land-only temperatures for February were more than three degrees above the 20th century average for only the second time.
The sea-only February temperatures were the third highest on record, behind 1998 and 2010, both years with strong El Niños.
The Weather Pattern Over The US In February
A relentless deep trough in the jet stream brought record-breaking cold and snow to the eastern US in February, while a ridge on the west coast caused record-breaking warmth and a continuation of the California drought.
This general pattern has been in effect since last winter.
There are indications that the El Niño in the Pacific Ocean, despite the fact that it’s weak, could break the pattern and bring beneficial rain to California and relief from the cold in the eastern US.
Seeing will be believing, and in any case, the change of seasons will inevitably bring a warmup to the eastern states.
Temperatures For December, January, And February Combined
Global temperatures for the winter months were similar to those of February, but there were hemispheric differences:
The Northern Hemisphere had a clean sweep of hottest temperatures for combined land and sea, land only, and sea only. The Southern Hemisphere reported their fourth, ninth, and fourth warmest respectively. Keep in mind that it was summer in the Southern Hemisphere.
Trends in precipitation are much harder to discern because they are subject to large single-occurrence events.
Consider this about precipitation statistics for all but the rainiest places. The mode (the number that occurs most often) of daily precipitation is ZERO. In other words, more days have no rain than have rain.
The median (the middle number if you line them up from least to greatest) is, therefore, also ZERO.
The arithmetic mean (what we normally think of as the average: the sum of all the numbers divided by the number of numbers) is about a tenth of an inch, but more than ten inches can fall in a single day.
Some of the highlights of February precipitation:
- The terrible drought in California, now in its fourth year, continued.
- Central Europe was very dry.
- A swath of wet weather, coinciding with a southern branch of the jet stream, stretched from the Mediterranean across the Middle East and into central Asia.
- Parts of southern South America were very wet.
- Guam in the North Pacific Ocean had its driest February ever.
- Vanuatu in the South Pacific had a very dry February before devastating Severe Tropical Cyclone Pam struck in March.
Ice And Snow Cover
The total sea ice extent for the Arctic and Antarctic combined was 120,00 Square miles below the 1980-2010 average. As usual, the Arctic ice extent shrank and the Antarctic ice extent grew. there is still no adequate explanation for this dichotomy.
The Northern Hemisphere’s snow cover in February was 230,000 square miles above the 1981-2010 average. This is consistent with global warming because warmer air holds more moisture. There are still plenty of places where it’s cold enough to snow.
The World Is Getting Hotter
The earth is warming due to an increase in greenhouse gases. Birds migrate earlier; fish spawn earlier; flowers bloom earlier. What evidence of climate change do you see?
Let Decoded Science know with a comment.
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