We’ve known for a long time that an increase in CO2 in the atmosphere could be good for plants. That has now been demonstrated at the global level for the first time. Using satellite data, researchers have been able to piece together how vegetation has changed between 1982 and 2009. The findings suggest ‘greening’ across 25-50% of the land surveyed, with 4% of places seeing less vegetation.
There are two reasons why climate change would make the world greener. First, rising CO2 levels will encourage plant growth. Commercial growers have been pumping CO2 into their greenhouses for years, so that’s well documented. If the effects can now be seen around the world, that’s striking evidence that we are changing the chemistry of the planet.
Secondly, the world is warming and extending the growing seasons in colder regions. Places that were previously frozen are opening up to more plant life for more of the year, such as the Tibetan plateau. Changing rainfall patterns have also brought more rain to dry areas such as the Sahel. Again, the changes in these places is evidence of a warming world.
There are other reasons for the greening in the mix too. Some of it is down to land change, such as new irrigation or reforestation, and some down to the use of fertilizers. But 70% of the observed greening is attributable to rising CO2 levels.
Is this a positive side of climate change? Sure, and there will be others, depending on where you live. But these benefits pale into insignificance compared to the downsides. No amount of plant growth is worth the extreme weather, rising sea levels, biodiversity loss and health risks of a destabilised climate. Any benefits may prove temporary anyway, as warming rises further and higher temperatures start to erode any gains.
So declaring climate change to be a good thing because of increased plant growth is a bit like welcoming a house fire because it helped you declutter the garage.
Here’s a quick summary of the story from NASA: