New climate insights: is the current situation more critical than expected?
An international study reveals critical factors related to climate change. Spring, which starts earlier, means that plants begin to grow earlier and earlier. This was initially rated as positive, since the general assumption was that it would bind more carbon (CO₂) from the earth's atmosphere. An international team of researchers has now refuted this assumption and shows that premature plant growth does not bind more, but less, CO₂ over the course of the year. The result: the situation of the global climate is even more tense than previously thought!
Until now, the prevailing opinion was that plant growth, which started earlier and earlier, led to increased biomass, which could then also bind more carbon. Many people saw this effect as a possible slowdown in climate change. International researchers with the participation of the University of Augsburg, the University of Leeds and the Vienna University of Technology, as well as research groups from the USA took a closer look at this effect and were shocked to find that the opposite was more likely to be the case. The scientists published their findings in the renowned science journal “nature”.
Evaluated with the satellite
Using satellite data, the team was able to determine and evaluate the green biomass of the past 30 years. "We have analyzed satellite images from the past thirty years - the entire globe north of the 30th parallel was examined, from southern Europe and Japan to the tundra regions in the far north," explains lead author Professor Dr. Wolfgang Buermann in a press release on the study results.
The researchers were able to identify the growth pattern of the vegetation based on light reflections. Wherever there is a lot of green biomass, green light is absorbed and infrared light is reflected, the scientists explain. Point by point around the world can be determined when and how much photosynthesis takes place - and also how much carbon is bound. This analysis shows that in many areas, an early spring leads to reduced biomass production in the following summer and autumn.
A rethink is necessary
"The climate models used up to now have to be adjusted - the situation of the global climate is even more tense than previously thought," emphasizes climate expert Buermann. The study is the first research to examine the effect of premature plant growth on a hemispherical scale. The data clearly show that the northern hemisphere is actually greener in spring. However, this effect is usually associated with the fact that less biomass is produced in the following summer and autumn.
Why does this effect occur?
After a green spring, a dry summer and autumn often come. The exact reasons for this are still unclear. The researchers suspect that increased plant growth in spring increases water consumption and evaporation. As a result, the soil moisture would drop and the plants would no longer have enough water available. The study team also believes it is possible that certain plants only have a naturally prescribed growth period that cannot be extended.
Violent consequences for our climate
"These mechanisms are complicated and vary from region to region," added co-author Dr. Matthias Forkel from the Vienna University of Technology. Even though many factors are still unknown, the data clearly show that the productivity of plants decreases in years with a warm spring. Previous climate models have not yet taken this effect into account and would have to be adjusted - in an unpleasant direction. "We have to assume that the consequences of global warming will be even more dramatic than previously calculated," said the conclusion of climate expert Professor Dr. Wolfgang Buermann. (vb)