climate change Pyrenees causing the snowpack to melt about a month agothat trees grow taller and ‘thinner’ the permafrost, that is, the icy cover of the ground. One of the consequences will be the contribution of meltwater during periods outside the current period and the growth of forests at levels that do not exist at present.
How is global warming affecting the Pyrenees?
Since it is a mountainous area, the changes caused by global warming are observed faster or with a more pronounced increase. We can confirm that although the glaciers in the Pyrenees are very small and have been reducing their thickness for 200 years, this decrease has been more pronounced in the last 40 years.
And what condition is the snow cover in?
The thing about snow is that we have a lot of variability. One year there is a lot of snow and the next, very little. Therefore, it is very difficult to see the changes. What happens is that the snow cover disappears sooner, it no longer lasts for months. Some time ago, the snow blanket could stay until the end of May in a very relevant extension; today this extension declines much earlier, at the end of April.
Is this because it melts faster or because there is no precipitation in the form of snow?
If we talk about climate trends, we do not observe large changes in precipitation, but changes in temperature. The temperature rises more markedly, especially in spring or summer. That way, even though we’re accumulating similar amounts of snow, the snow will disappear sooner as higher temperatures build up sooner. It will be related to thermal increase rather than precipitation trend. There are years when it snows a lot, there are years when it snows less, but this happened to us 50 years ago.
For example, although more precipitation is expected in the Alps, there will be less precipitation in the form of snow. Is this also expected in the Pyrenees?
Yes, that’s what climate change scenarios show us about the Pyrenees. In the future, although there will not be a significant increase in temperature in winter as in summer or spring, the snowfall will come later and end sooner. If we add to this that it will be warmer in the hot season, the result will be less snow cover withstand and therefore more exposure time of mountain and high alpine grassland to solar radiation and therefore to temperature. , they can grow more.
In other high mountain areas like Mount Teide, what scientists clearly see is an increase in nighttime temperatures. Do you see a similar trend?
These tropical nights can be observed in urban areas, but we find another peculiarity to study them in mountainous areas, and that is that it is difficult to get beyond in mountainous areas, while other places have climate records of up to 100 or 80 years. The 80’s and especially if we’re at a higher altitude. Therefore, we do not know very well whether we are experiencing an increase in truly warm nights or a global climate trend.
There are several effects cited for the ecosystem of the Pyrenees, any of which are already visible?
What we see in the Pyrenees is that in recent years trees have gradually colonized higher areas. The bushes reach the areas where previously there was only grass, because there is a better temperature and there is no snow; and in time they will form a forest. This is a remarkable change for the ecosystem because forests also demand water. The forest mass will cause some of the precipitation to return to the forest itself and not to the river beds.
Another impact highlighted by a recent study on the Alps in Switzerland is the reduction of water resources in the future.
For example, in the Ebro valley, there will be an increase in water between May and June as the snow will melt. By shortening the time we have snow on hand, maybe it will melt in March or April, meaning we’ll have the water we have on hand much sooner during a warmer time of year. This will force us to learn to manage river channels with different characteristics.
“The bushes are reaching areas where there was only grass before because there is better temperature and there is no snow and in time they will turn into a forest”
Your research team also found evidence of permafrost in the Pyrenees, what does that mean and what are the risks of melting?
Yes, some parts of the Pyrenees have permafrost (frozen ground) in the snowiest areas. Normally, snow protects it from solar radiation and the temperature rises, but if there is less snow, the permafrost will be exposed to the summer heat sooner and will gradually disappear.
And what consequences could it have?
His disappearance in the Pyrenees does not bear much weight, except for people who may be in the vicinity. However, in other parts of the planet, such as Siberia, where all the soil is permafrost, there is an instability of the terrain, where there are areas with roads and buildings. In addition, in these areas where permafrost occupies an important place, gases can be released into the atmosphere. The worst consequence in our latitudes is the destabilization of certain walls. This can have safety issues on a climbing route, and if anyone was climbing this wall, their life would be in danger.