Scientists from Potsdam Institute for Climate Impact Research have reported that temperatures in the Arctic are increasing due to human-induced global heating. This could lead to prolonged periods of severe heat and droughts throughout the summer months in Europe, America, and elsewhere in the Northern Hemisphere. The Northern Hemisphere’s mid-latitude countries are those in northern Europe that have a climate with high temperatures. They exclude the US, Canada, Mongolia and Alaska. Their findings were published in Science by the researchers (citation below). In the warmer northern regions, extreme heat and prolonged periods of drought are more likely to occur during the summer months. Dr. Dim coumou is the lead author. He said that climate change can cause great disturbances in the skies above us, which could have devastating effects on the ground. You might think that a reduction in storm activity is a good thing. However, this decrease leads to greater persistence of weather system at the Northern hemisphere’s mid-latitudes. “In summer storms transport cool and moist air from the oceans, to the continents, providing relief for periods of intense heat. Warm weather conditions are made more durable by slack periods. This can lead to heat buildup and drought. Previous research had focused primarily on winter storms as they cause the most damage. The authors noted that the average storm activity in winter is relatively stable compared to summer. According to satellite data and observational data, the incidence of storm activity in Northern Hemisphere regions at mid-latitudes during summer has decreased significantly. Summer storms seem to be occurring less often, less intensely or both. Scientists calculated the energy of wind speeds by studying synoptic and other types of turbulences. The energy is the result of the interaction between low pressure and high pressure systems within the atmosphere. It’s ten times lower than 1979.. Jascha Lehmann (a PhD candidate) said that “unabated climate changes will likely further weaken summer circulation patterns, which could cause heat waves.” Climate simulations for next decade, the CMIP5, also show the same link as observations. “The recent high temperatures could be just the beginning.” The rising arctic temperature may have caused circulation changes. According to the authors, the Arctic’s rapid warming may explain the observed changes. While we all understand that global warming can be caused by greenhouse gas emissions, few people realize that the temperature rises faster in far northern regions. The far northern areas of our planet, which were once covered with ice and are now ice-free are more dark than white ice. They reflect less sunlight back into the space. The water is heated, which increases the temperature. The atmospheric temperature difference in the Northern Hemisphere’s cold polar regions and other parts of the Northern Hemisphere is reduced. Air must move in order to circulate. The greater the temperature difference, the more movement. Scientists explain that if this difference shrinks, then the jet stream weakens. This weakening may be responsible for the decline in summer storm activity, they claim. Dr. Coumou stated that no matter what angle you take at heat extremes the evidence points in the opposite direction. Heat extremes don’t just rise because the earth is warming, they also increase due to climate change affecting airstreams important for shaping weather. “We observed that weather becomes more consistent, which results in heat extremes at monthly timesscales. The risk of heat waves with high impact is expected to rise.” Citation: Dim, Jascha and Johanna Beckmann. Science. “The decreasing summer circulation at the Northern Hemisphere’s mid-latitudes” Published online 12 February, 2015. DOI: 10.1126/science. 1261768.
