Lack of Reliable Climate Change Predictions

When it comes to the impact of climate change on ecosystems, we still have large knowledge gaps. Most experiments are unrealistic because they do not correspond to projected climate scenarios for a specific region.

Thus, we lack reliable data on what ecosystems might look like in the future, as a team of biodiversity researchers from Central Germany show in the journal “Global Change Biology”.

When it comes to the impact of climate change on ecosystems, we still have large knowledge gaps. Most experiments are unrealistic because they do not correspond to projected climate scenarios for a specific region. As a result, we lack reliable data on what ecosystems might look like in the future, as a team of biodiversity researchers from Central Germany show in the journal “Global Change Biology”. The team reviewed all experimental studies on the topic. The researchers are now calling for the introduction of common protocols for future experiments.

The facts that climate change is man-made and that it will alter ecosystems are indisputable. However, there is debate about its extent and its consequences. “In order to predict how plant communities will react to climate change and what ecosystems of the future will look like, we need realistic field experiments worldwide,” says Humboldt Professor Tiffany M. Knight from Martin Luther University Halle-Wittenberg (MLU) and the Helmholtz Centre for Environmental Research (UFZ). She heads the group “Spatial Interaction Ecology” at the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig. According to Knight, field experiments are a necessary tool for understanding the effects of climate on plant communities. “Nature is complex and plant communities are structured by many interacting environmental factors. Experiments can specifically isolate the role of climate factors, such as precipitation and temperature,” says Knight.

The researchers conducted an extensive literature review on the subject, searching for field experiments on the relationship between climate factors and plant communities. “In these experiments, temperature and precipitation are altered to investigate their effects on the plant community,” explains Dr Lotte Korell, a member of Knight’s research group and lead author of the study. The team was able to identify a total of 76 studies that manipulated either precipitation, temperature or both.

“We were surprised to find that most of the studies were not based on the actual climate forecasts for the specific geographical regions. In many cases they were not even close,” says Korell. According to her, this mismatch between the climate manipulations in field experiments and climate projections for the regions is due to many factors. Many of the experiments were set up to address questions unrelated to climate change, or were set up before more precise climate projections were available for some regions. “There’s nothing wrong with the science in those experiments. They are just not suited to answer the questions we are now asking”, says Tiffany Knight.

Reference:

Korell L., Auge H., Chase J., Harpole S., Knight T. We need more realistic climate change experiments for understanding ecosystems of the future. Global Change Biology (2019). doi: 10.1111/gcb.14797