2015 warmest year on record globally

Published 7:00 am Tuesday, December 1, 2015

Call me self-centered, but the weather I usually care about is the weather I’m going to feel when I walk out my door.
But, as the old song tells us, the shin bone is connected to the knee bone, and the knee bone is connected to the thigh bone, etc. Our local weather is connected to what is going on in the atmosphere, oceans and continents around the world.
But, despite the knowledge scientists have gained over the past century about the earth’s weather and climate, there’s still a lot about those connections that is unknown.
With all of that in mind, I pass along the following news: 2015 is almost certainly going to end up as the warmest year on earth going back through the era of modern weather record-keeping to 1880.
That was the announcement from the World Meteorological Organization last week. The WMO was able to issue this early estimate because 2015 already has been so much warmer than average that December would have to be almost impossibly cold to keep this year from setting the record.
Not only will 2015 likely set a new record for warmth, the WMO’s analysis shows that the five year period from 2011-2015 has been the warmest five year period since the late 1800s.
It is important to be clear about what this means and doesn’t mean.
The number being referred to is the surface temperature averaged across an entire year and averaged across the entire planet. The WMO’s preliminary estimate of the earth’s average surface temperature for 2015 is 58.5 degrees Fahrenheit. That’s between one and two degrees Fahrenheit warmer than the long-term average.

That may seem like an insignificantly small number. But, global averages do not change very much from year to year, so a one- or two-degree difference is actually quite large.
What this average doesn’t mean is that it was warmer than normal everywhere, all the time. It was still colder than average at many places around the globe, and at many times during the year.
It’s simply impossible for anyone to discern from their local weather during a single year whether the annual average for the planet is getting warmer or colder.
A major contributor to 2015’s record warmth is the ongoing extremely strong El Nino. El Nino is the oceanic and atmospheric event characterized by warming of the sea surface temperatures in the tropical central and eastern Pacific, which occurs every three to seven years.
The majority opinion among climate scientists is that the addition of carbon dioxide to the atmosphere through the burning of fossil fuels has also contributed to a warming trend seen over the past century. In fact, a new record high was set in 2015 for global average concentration of carbon dioxide.
How much did the increased carbon dioxide contribute to this year’s record warmth compared to the natural variability of the earth’s temperature? That falls into the “still unknown” category.
Regardless, even though the global climate appears to be warming, when you walk out the door tomorrow, and for the rest of the week, you’ll notice it’s a lot cooler than it has been over the last week. After all, it is December.

By Skip Rigney

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