“The test of a first-rate intelligence is the ability to hold tow opposed ideas in the mind at the same time, and still retain the ability to function.” – F. Scott Fitzgerald Meanwhile we’ve got this updated Fox news global warming alert, it is still cold, in fact it is getting colder, much colder, environmentalists telling me DUHHH “because it’s winter”…IT IS FREEZING! We’ve heard a lot of talk lately from deniers that cold temperatures are proof that there is no such thing as global waming. It looks like it will be an annual event for me to remind people that winter still follows summer. So, before we get started, a little review. It was a cool summer, right? Chicago, New York, places like that, so, how can it be global warming? This is how. Look at the context. These blue dots over North America represent below average temperatures for the summer, June, July, August, what we call climatological summer.
But look at the context, they’re lost in a sea of red dots, across much of the rest of the globe, just a couple other blue dots here and there, those red dots are above average temperatures. What that translates to in terms of a ranking, for this summer and for august, globally, second warmest on record, period of record going back a little more than a century. June through august globally, the third warmest on record, the oceans, which had cooled for a couple years, now recovered with a vengeance, August the warmest on record, June through August, also the warmest on record, and in the southern hemisphere, August was the warmest on record. The warm summer was followed up by a very warm november, globally, including abnormally warm temperatures in north america. Ironically, unseasonal warmth set the stage for dramatic winter weather, when temperatures did drop in december.
Let’s talk about why we’re seeing such a huge and significant lake effect event. The Great Lakes themselves, the water temperature there is still some 3 or 4 degrees warmer than it should normally be this time of year, because of a very mild November. Now again, its very cold air right now, its about 17 degrees, the cold air is coming over these warm lakes, picking up all this moisture, and dumping inch after inch of snow down wind, and, people, waking up on your friday, dealing with perhaps 2 to 4 feet of snow. People love to talk about the weather, and a series of strong storms and cold temperatures in December and early january sparked a lot of discussion. What scientists are telling us is that an important circulation pattern, the arctic oscillation, is in it’s negative phase. Normally, in the positive phase, the arctic oscillation produces strong winds around the arctic that keep cold air bottled up. When the oscillation is in its negative phase, cold air spills out of the arctic, and flows into north america and eurasia. Paradoxically, while temperate zones feel an arctic chill, the arctic itself becomes warmer than usual, exactly the effect that has been observed over the last several weeks.
The UK meteorological office produced this map, and described the observations. “Canada, North Africa, the mediterranean, and south-west Asia have all seen temperatures above normal, in many places by more than 5° C, and in parts of northern Canada, by more than 10° C.” When we look at the graph of the monthly arctic oscillation index, we can see that the current one is the strongest negative since the 1970s, which is why many people were surprised by the blasts of cold air, that are expected under these conditions. One effect was on air circulation over western europe, which normally flows from the west over the atlantic, delivering warmer air. Under the negative arctic oscillation, the warmer winds are blocked, and most of of the air flow is cold arctic winds, leading to snow and cold in many european countries. This diagram from NOAA shows the pattern of warmth in the arctic and unusual cold in mid latitudes around the northern hemisphere.
Dr Mark Serreze, director of the National Snow and Ice Data center, told reuter’s news agency: “It’s very warm over the Arctic, with air temperatures locally at 10 to 15 degrees F (5.6 to 8.4 degrees C) warmer than they should be in certain areas,” This map from NASA also shows the pattern, which was well illustrated in a BBC report with graphics from the UK Met office. This MET office maps show’s today’s temperatures around the northern hemisphere. There’s cold air over us, but warmer air elsewhere. Look further south and east, there’s an unusually warm band of air there. Then, further east, and over China, another very cold pocket. But just as the arctic was unseasonably warm, other areas of the globe also were not feeling the cold. While much of the Northern Hemisphere suffers from one of the hardest winters in years, the thermometer is shooting way up, down under. On Monday, Melbourne was melting with highs soaring to 110 degrees fahrenheit, monday night, Melbourne sweltered through its hottest night since 1902, the temperatures topping 34 degrees Celsius, or 93 degrees fahrenheit.
Most people think of global warming as a process where the planet sets new warming records year after year. A clearer picture comes in a new study from the National Center for Atmospheric research, described here by senior scientist Gerald Meehl. But what we noticed is in the last 10 or 20 years there’s been this ratio of about 2 to 1, for every 2 record high maximum temperatures, there’s only been about one record low minimum temperature set, on average over the US. We looked at a model simulation going off into the future, and in this model simulation we had a scenario where we are increasing carbon dioxide and other greenhouse gases going off into the twenty first century. And as the climate continued to warm, this ratio continued to grow. In other words, you kept having more and more record high maximum temperatures, fewer and fewer record low minimum temperatures. So by the mid twenty first century, this ratio, which is now about 2 to 1, was about 20 to one, by the end of the century, with this continued warming, this continued change in the distribution of records, the ratio is about 50 to 1.
One of the messages of this study is, you still get cold days. Even at the end of the twenty first century, in the model simulation, when the climate’s warmed up by 3° or 4° Centigrade on average across the US, you’re still setting record low minimum temperatures on a few days every year. So, people always get very alarmed if there’s a cold snap in the winter, and they say, “what’s happened to global warming? We’re freezing out here.” And you say, well, that’s just the weather. In the northeast we’re talking temperatures well above average, Boston heading up to 43, warm in New York at 44, DC, we’re in the 50s, that’s about 10 degrees above average. And no cold in the midwest either, we are well above average here, friday temperatures 20 degrees above average in Bismark, at 39 degrees, we’ll be warm in Kansas City, in Denver will be mild, and in Great Falls, Montana, about 20 degrees above average, the warmth hangs on on saturday, all across the midwest.
When I look out at the world from a limited perspective, my senses tell me that the earth is flat. For thousands of years, most human beings probably believed that this was so. But in a technological, scientific world, our perception is greatly expanded, and we have a much larger view of the world and our place in it. We need to understand the larger perspective about our changing climate as well. Sophisticated instruments and advanced science show us details that our senses could never see, and recent satellite measurements show, that in fact, on january 13th, global temperatures were the warmest for a january day in the satellite record. And this week, NASA released data showing that 2009, was the second hottest year in the instrumental record. We’ll be looking more at this new data in coming weeks and months. The science of global climate is vital for us to understand if we are to pass along to our children a planet that is liveable, diverse, and abundant.
It’s the most important task this generation will undertake, and you can keep track of our progress right here, on climate denial crock of the week..