How winters are disapperaring in Sweden

Photo: Artificial snow for cross country skiing in Falun’s ski stadion.

Two and a half years ago I moved to Southern England from Sweden. One thing I have really missed since relocating are the Scandinavian winters, especially being able to do sports like cross country skiing.

For this reason, my husband and I decided to go cross country skiing in Sweden over the February holidays this year. We chose to go to Falun in central Sweden. The town has a long tradition of cross country skiing, being the location of Sweden’s National Cross Country Skiing and Ski Jumping Centre as well as having hosted four Nordic Skiing World Championships in the past.

As a child, I often saw Falun’s surroundings on TV when watching international cross country skiing competitions, its forests covered by thick snow. Until recently the town was indeed a place with guaranteed snow for skiing during the winter months, but not anymore. Climate change does not care about long winter sport traditions.

When we arrived during the second half of February, temperatures were constantly above 0 degrees Celsius, peaking at 8 degrees Celsius. No need to say that there was no real snow for skiing. With many trees starting to sprout due to the high temperatures it felt more like spring than Scandinavian winter.

We were lucky that there was at least some artificial snow prepared for cross country skiing in the ski stadion. In the image above you can see me in the ski stadion in front of the ski jumping hills. The lack of snow in the image is quite obvious.

When looking at the snow depth map provided by the Swedish Meteorological and Hydrological Institute (SMHI) for the last seven days it can be seen that half of the country does not have any snow. The Southern half of Sweden as marked as ”bare ground”.

According to the Japan Times temperatures had climbed to 5 degrees above normal in Southern Sweden and 10 degrees above normal in Northern Sweden during January. The article tells us that the situation is the same in Norway, Finland and North West Russia. What I personally found most disturbing was the account of a Norwegian town that had reported 19 degrees Celsius this January.

Climate change is here to stay. Winters in Sweden and other Scandinavian countries will continue to get warmer and shorter. In many regions winters will disappear completely.


How climate change and a tiny beetle destroy German forests

Image: Forest in the German Harz Mountains that has been damaged by the bark beetle.

At the moment the news talk a lot about of the wildfires in the Amazon and the Arctic. But climate change and human activity also pose other dangers to forests, as can be seen in Germany.

During this summer family and friends had told me quite a bit about the extreme heat wave and drought in Germany. I had also heard through the news that German forests were suffering as a consequence.

However, none of this prepared me for what I saw when visiting my family home in the Harz Mountains in the middle of Germany.

As long as I can remember, the area around my home town has been covered in dense spruce forests. Much of my childhood was spent roaming these forests, looking for interesting animals and playing with friends.

When we approached my home by car at the end of August it was very clear, that this vast coniferous forest is sick. Like in the image above, many trees had lost their needles and large proportions of the forest had been felled leaving empty, moon-like landscapes.

You might think that the trees are only dying because they do not get enough water, but it is not as simple as that. Yes, the drought and hot temperatures limit the trees water supply. Nevertheless, the coniferous trees are still able to get enough water for their basic functions like photosynthesis. But the lack of water damages the spruce’s ability to defend against pests like the bark beetle.

The bark beetle is a tiny insect measuring about 6 mm (0.25 inch) that reproduces inside tree bark. The male and female drill into a tree to build a chamber for their eggs. After hatching the larvae bore away from the egg chamber feeding on the inner bark. This harms the part of the wood which transports water and food. In addition, the plant’s ability to form fresh bark is decreased. As a consequence, the tree will slowly die.

Like our skin the bark of a tree keeps out diseases and parasites. The normal response to a bark beetle attack is the secretion of tree sap to suffocate the beetles and their larvae. But in the event of extreme drought and heat, the trees cannot produce enough sap. Like the human immune system, the tree’s defenses do not work well under extreme stress.

The bark beetle has always been a pest in the Harz Mountains, my home area. One reason for this is that the trees are grown as a monoculture that mainly includes spruce. Deciduous trees are much more resilient towards the bark beetle and can form a natural barrier when planted in between spruces. Unfortunately, the forest is cultivated and managed by the timber industry which is only interested in the fast-growing spruce.

Despite the old monoculture problem, the current explosion of beetle infections is unprecedented and a consequence of climate change. Summers have continuously gotten hotter. During this year’s July heatwave even the – normally chillier – Harz Mountains reported temperatures above 35 degrees Celsius over several days and many new temperature records. At the same time the amount of rainfall in summer has decreased. Also, warmer temperatures allow more bark beetles to survive the winters.

The sad part of this story is that the National Park in the Harz Mountains is most severely affected. The park was founded in the early 1990s on former timber industry lands, covered with spruce monocultures. The aim was to let the land develop naturally into a mixed forest over many years. Now climate change and the bark beetle seem to be speeding up this process by destroying most of the spruce trees.

While the timber industry removes damaged wood to prevent healthy trees from getting infected, this cannot be done in a National Park where nature must be left to its own devices. As a result, the areas containing sick and dead trees are much larger in the National Park compared to the timber forests. This development could be a chance for deciduous trees to colonize the National Park faster forming a natural, mixed forest.

The future of the timber industry forest is not as clear. It is obvious that spruce monocultures will not survive the changes that global warming brings for much longer. There are now discussions in Germany to introduce foreign tree species that can cope better with heat and drought to replace the spruce. Maybe some forestry commissions will even move towards more natural mixed forests.

Looking at the dead trees and moon-like landscapes right now, I am wondering if this area will ever regain its former beauty. I cannot help but ask if my own children will ever see the vast forests of my own youth here. You do not need wildfires to destroy large amounts of forest. The trees in Germany are being destroyed by climate change and a tiny beetle.

I believe that the Harz Mountains and other German forests will eventually recover, the National Park by slowly developing into a natural, mixed forest and the timber forests possibly by introducing foreign tree species. But there is a chance that the spruce trees, that have been so iconic for German forests over centuries, could be gone.

How does carbon dioxide cause global warming?

carbon dioxide

Every sixth grader today knows that carbon dioxide causes global warming. Or at least every sixth grader outside the United States knows this. But why is carbon dioxide a green house gas? I tried to answer this question with the help of an infographic (see above).

From a chemical point of view, heat is motion of molecules and atoms. The more movement is happening on a molecular level, the more heat we feel on a human level (also called macroscopic level). Carbon dioxide is a molecule that is very good at this kind of movement, you could say it is a very athletic molecule. All molecules and atoms in any gas are able to move in all directions in space, but carbon dioxide can even carry out certain movements inside the molecule. These movements are called vibrations. Carbon dioxide can carry out three different vibrations, the symmetric stretch, the asymmetric stretch and the symmetric bend, which can be seen in the infographic above. You can even watch them here. One could say that while other gas molecules or atoms can only run around to create motion, carbon dioxide can additionally jump, wave with its arms and do sommersaults.

The three vibrations are the reason that carbon dioxide can store heat much more efficiently than other gases in the atmosphere where it takes up heat that would normally be lost into space. This means the more carbon dioxide we have in the atmosphere, the more heat is stored on earth. Other green house gases like methane (which eventually converts into carbon dioxide in the atmosphere) have a number of different vibrations as well and work on the same principle. Even water can carry out different vibrations and is a good heat store too. However, it normally falls back to earth as rain or snow within a few days and does not stick around in the atmosphere long enough to do much damage. Carbon dioxide, on the other hand, cannot easily leave the atmosphere and it takes about 100 years for it to do so.

So what about other gases in the atmosphere? Air consistes for the most part of nitrogen (78 %), oxygen (21 %) and argon (1 %). Argon consists of only one single atom and does therefore not have any vibrations. Nitrogen and oxygen both are made up of of diatomic molecules which means two atoms are held together by one bond. This enables them to carry out only symmetric stretches. This is, however, not enough to store heat as efficiently as carbon dioxide does.

Is the future of the lithium-ion battery green?

Image credit: Stéven Renault, 2014, CC BY-SA IGO 3.0.

Lithium-ion batteries (LIBs) are normally considered an environmentally friendly technology, for example in electric vehicles where they are replacing climate gas spewing combustion engines. A widely unknown fact is that the production of these batteries causes a lot of pollution and climate gas emission too. I have talked to Dr. Stéven Renault, a researcher at Ångström Advanced Battery Center, Uppsala University (Sweden), who is trying to tackle this problem regarding the manufacturing process of LIBs.

Materials currently used in commercial LIBs are graphite and metal oxides such as cobalt oxide and manganese oxide. They are obtained via mining and subsequent chemical extraction. These processes create a lot of climate gas emission, pollution and waste. Metal oxides like cobalt oxide are also mainly mined in central Africa where unethical working standards and child labour are involved. In addition, it is very difficult to recycle lithium from these batteries when they reach the end of their life time.

The goal of Renaults research is to develop batteries from organic materials with a completely sustainable life cycle, in other words a ”green” battery. This means that the battery materials are produced from renewable sources like plants using environmentally friendly extraction methods. The contained lithium can also be easily recycled at the end of the batterys life span. This approach also focusses on using non-edible plants, for example trees, or parts of plants like the stems of crops to avoid conflicts with food production.

Nevertheless, Renault admits that green batteries still have some drawbacks, for example low energy densities. For this reason, they cannot yet compete with state-of-the-art materials (like graphite, cobalt oxide and manganese oxide) in mobile phones, laptops and electric vehicles. But the situation might change in the future if the lithium price keeps rising and lithium recycling becomes more attractive. In 2016 alone the price of lithium has increased by 14 %. Another issue is the lack of studies regarding battery safety. (We all have seen the images of burning mobile phones and laptops.)

To the question, if it is possible to buy these green batteries yet, Renault says that a Japanese company had unsuccesfully tried to commercialize them. But the competition of the standard batteries was too strong. Now a German company is working on green batteries for niche-markets where energy density matters less than in portable electronics and cars. This is where we will probably see the commercialization within the next two years.

Renaults own greatest accomplishment is the development of dilithium benzene diacrylate, a compound for use in LIBs that can be extracted from pine resins or alfalfa. When the end of the battery life cycle is reached lithium carbonate can be retrieved via ”thermal desctruction”, in other words burning, of the material. The lithium carbonate can then be used together with a precursor (benzene diacrylic acid) extracted from pine resins or alfalfa to create new dilithium benzene diacrylate to be used in another battery. This recycling process is shown in detail by the image above.

It will be very interesting to see when and in which form green batteries will be commercialized. Maybe we will be able to buy them for certain applications not too long from now.

Some good news

Climate change, extinction of species, de-forrestation, multi-resistent germs, chemical warfare and so on. The media – also science-based – is  full of bad news.

This is the reason I wanted to write about good news in science for a start. There are some good news out there, but we often fail to click on them and share them as often as we do with the bad ones.

So, here it comes, the good news of the day.


Solar power is becoming cheaper than electricity generated from fossil fuels!

In the end of 2016, unsubsidized solar power projects have been able to outcompete coal and natural gas for the first time. And guess what? The cost for solar panels will continue to fall. Wind energy is becoming cheaper too, but at a lower speed.

This means investments in renewable energy projects are no longer only for Green Party members, but a real alternative for profit-orientated companies and billionaires. This can accelerate the expansion of solar and wind power plants. Especially developing countries could profit from this development to build and extend their national power grids. Here is another great aspect: Solar and wind power plants create more jobs than their fossil fuel counter parts!

Unlike coal and natural gas, oil will most likely not be replaced as quickly since airplanes and the vast majority of cars run on oil-derived fuels. It is also necessary to make products based on plastics. But if we eventually switch over to electric cars, most of our oil production could become redundant like coal and gas. This would leave us with cleaner air and quieter cities, not a bad prospect, is it?