The Earth Has Become Greener — But the Balance of Vegetation is Shifting North and East

Illustrative photo. Source: Getty Images

As reported by Der Tagesspiegel, researchers from Leipzig University and the German Centre for Integrative Biodiversity Research decided to find out whether the geography of global vegetation has changed in recent decades.

Scientists hypothesized that as the planet warms, conditions for plant growth towards the poles should become more favorable.

It would be logical to expect that the center of green mass — a conventional geographical point reflecting the average position of all vegetation on the planet at a given moment in time — would shift more strongly in both directions: further north during summer in the Northern Hemisphere and further south during the warm period in the Southern Hemisphere.

To test the hypothesis, the team analyzed satellite images and climate models from 1982-2020.

However, the results were different. The center of green mass did shift, but not symmetrically. Researchers recorded a clear shift northwards during the northern summer period, as well as a noticeable drift to the east.

According to calculations, the global "green center" reaches its northernmost position in mid-July in the North Atlantic near Iceland, and its southernmost in March off the coast of Liberia.

What is the reason?

The researchers note that the changes are likely related to both climatic factors and human activity.

The northern shift can be explained by the lengthening of the growing season and milder winters in the Northern Hemisphere, where large landmasses allow for easy greening even in winter. However, the authors emphasize that this interpretation remains a hypothesis for now and requires further research.

The researchers link the eastward shift to large-scale greening hotspots identified in India and China. In the case of China, according to the authors, targeted reforestation is the cause with a high degree of certainty.

Why this is important

According to the authors, their work, the results of which were published in the journal PNAS, offers a new way to assess the state of the biosphere. Tracking the center of green mass allows for an integral measurement of how the living cover of the planet changes under the influence of climatic shifts and land-use transformation.

The authors note that a similar approach can be applied to other global processes: determining the "white wave" of ice cover, the "blue wave" of terrestrial water resource accumulation, and the "red wave" of fires. This would allow us to see how the Earth's living surface is reorganized as a whole.

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