An international team of 21 authors from 17 institutions in seven countries has just published a study in the journal Natural Climate Change showing that, as the cover of snow and ice in the northern latitudes has diminished in recent years, the temperature over the northern land mass has increased at different rates during the four seasons, causing a reduction in temperature and vegetation seasonality in this area. In other words, the temperature and vegetation at northern latitudes increasingly resembles those found several degrees of latitude farther south as recently as 30 years ago.In other words, everything we know about farm belts, growing seasons, traditional foods, forest densities, animal migrations, and local weather patterns is changing. Rapidly.
On the amplified greenhouse effect, Prof. Ranga Myneni, Department of Earth and Environment, Boston University and lead co-author says "A greenhouse effect initiated by increased atmospheric concentration of heat-trapping gasses -- such as water vapor, carbon dioxide and methane -- causes the Earth's surface and nearby air to warm. The warming reduces the extent of polar sea ice and snow cover on the large land mass that surrounds the Arctic ocean, thereby increasing the amount of solar energy absorbed by the no longer energy-reflecting surface. This sets in motion a cycle of positive reinforcement between warming and loss of sea ice and snow cover, thus amplifying the base greenhouse effect."Feedback loops.
"This may portend a decoupling between growing season warmth and vegetation productivity in some parts of the North as the ramifications of amplified greenhouse effect -- including permafrost thawing, frequent forest fires, outbreak of pest infestations, and summertime droughts -- come in to play," says co-author Hans Tømmervik, Senior Researcher, Norwegian Institute for Nature Research, Tromsø, Norway.With so many interrelated variables, the exact rate of declining seasonality cannot be predicted. Thus far, what has been observed is not happening as rapidly as the models show will happen, but that doesn't mean that there hasn't been plenty observed. For over a decade, we have known that climate change is driving epidemic diseases such as dengue fever into new territories. Of course, animals also are following the climate, and a 2011 study estimated that species are moving to higher elevations at a median rate of 11 meters per decade, and to higher latitudes at a median rate of 16.9 kilometers per decade. And that's not all. As the 2006 Stern Review of climate change impacts noted:
According to the authors, the future does indeed look troubling: Based on analysis of 17 state-of-the-art climate model simulations, diminishment of temperature seasonality in these regions could be more than 20 degrees in latitude by the end of this century relative to the 1951-1980 reference period.
Warming of 3 or 4C will result in many millions more people being flooded. By the middle of the century 200 million may be permanently displaced due to rising sea levels, heavier floods and drought.But in January, Nicholas Stern admitted he had gotten it wrong:
Lord Stern, author of the government-commissioned review on climate change that became the reference work for politicians and green campaigners, now says he underestimated the risks, and should have been more "blunt" about the threat posed to the economy by rising temperatures.We can't afford to play games or make half-measures. We have to treat the climate crisis as a crisis.
In an interview at the World Economic Forum in Davos, Stern, who is now a crossbench peer, said: "Looking back, I underestimated the risks. The planet and the atmosphere seem to be absorbing less carbon than we expected, and emissions are rising pretty strongly. Some of the effects are coming through more quickly than we thought then."