During all the years the climate debate has flourished, misunderstandings and conspiracies have often stood in line. It has been almost a rule that an opinion from a scientist has been contradicted from other side. The media have not made the debate easier when they often debate with equal numbers on each side of a given question.
Now I would like to take a discussion in advance, because in the coming days parts of Europe will be hit by cold weather – some places even very cold. I would expect comments that now global warming has been canceled, giving mor fuel to the climate debate. I hope the media will be wise enough to counter such allegations – and if they lack arguments, they can only take mine here.
The most important thing is that global warming should be seen – precisely – globally, because as it gets cold in a larger area around us, it does not tell anything about the global temperature. The United States experienced extreme cold weather around New Year, where the American president stated that he could then use more global warming. But he did not understand that we are talking about global temperatures.
The figure shows that the very cold area is just east of Denmark, while it is similarly very hot across Greenland and around the North Pole. In the USA it is very hot in the east and cold in the west – elsewhere in the world it can be seen that the red color dominates. So because we are just hit by a cold period for a short period of time, we should not turn it into a denial of climate change.
The other factor to be considered is the abnormal distribution of cold and heat. Normally we would expect it to be cold around the North Pole and also across the larger areas of Siberia, Greenland and Canada. But as the picture shows, that’s not the case. One of the reasons is likely to be found in the weaker jet stream, which is approximately 10 km above the earth’s surface about 60 degrees north. It is getting weaker because the Arctic under global warming is heated faster than the areas further south. A weaker jet stream is unable to maintain the cold where it usually is and accordingly the hot air will move abnormally. This means that we see the cold draw south and the heat north – exactly as we see it at the moment.
The unusual temperature conditions we can experience right now can therefore be seen just as a result of global warming. But actually it is not that cold! Over Denmark DMI does not expect temperatures below minus 10 degrees. This is partly due to the lack of snow-covered surfaces, but we just feel it very cold, because we are not used to low temperatures in recent winters.
Having said that, it is nice to see that after all it is possible to build a stable high pressure over Scandinavia. This weather type has been quite absent for many many months and given unstable wet weather throughout 2017.