The effects of climate change also affect the plant world, triggering adaptations that cause plants to move in search of conditions that are favourable to the survival of different species. Let’s examine this phenomenon and some specific cases.
The most widely accepted reconstructions say that about 56 million years ago a carbon dioxide bomb entered the atmosphere, increasing the Earth’s average temperature by 7-14 degrees Fahrenheit. This event is known as the Palaeocene-Eocene Thermal Maximum (PETM).
University of Wyoming palaeobotanist Ellen Currano, who studies the effect of the PETM heat on plants, found plant macrofossils dating back to the PETM during research in Wyoming’s Bighorn Basin. These fossils show that before the PETM, there was a forest of cypresses, plane trees, walnut trees and other species in the area. Research has shown that this environment was subsequently replaced by a forest of palm trees and other plants endemic to subtropical places. A scenario that could happen again in the not-so-distant future?
Scientists predict that over the next 100-150 years, the earth’s temperature could rise by roughly the same amount as it did during the PETM.
Plant reorganisation is therefore highly likely, but the question is how will it happen? It’s not easy to make global predictions, as it could occur in a clear and radical way in some areas of the planet and less noticeably in others.
To give a few examples: baobabs in Madagascar are experiencing a serious crisis. Research published in 2013 shows that global warming may soon render the habitats in which baobabs live unsuitable for them, as well as for other species that require similar conditions. Like the baobab, the cedar, the national symbol of Lebanon, is also disappearing. This ancient species once spread across thousands of kilometres of Lebanon’s landscape; today, only 17 square kilometres remain.
Cedars prefer cold climates and as temperatures rise they are forced to migrate, literally, in search of more suitable conditions. As they have little opportunity to seek more favourable climates by migrating to new latitudes, they tend to move to higher altitudes. Unfortunately, however, they have little leeway in that respect either, as even at high altitudes the climate is warming, leading to a proliferation of insects that destroy the leaves of cedars.
These are just a few of the many examples of plant reorganisation, and this is just the beginning.
At present, these changes are sporadic and not directly related to each other, but they are all sides of the same coin.