The Sahara Desert has provided the setting for many grand proposals for preventing climate change, ranging from covering the Desert in gigawatts of solar panels to irrigating the Desert to enable the cultivation of vast forests. But recent news from The Daily Climate provides an important lesson about transforming significant portions of the Sahara into a "more productive" carbon sink. The article explains that dust clouds from the Sahara provide a majority of the iron (a critical nutrient for plant growth) in the Atlantic Ocean and Amazonian Rainforest.
Dust clouds from the Sahara fertilize oceans and forests thousands of miles away. Source: The Daily Climate.
As even the authors of the irrigate-the-Sahara proposal note, covering the Sahara with solar panels, trees, or any other type of ground cover could have massive adverse consequences on ocean and rainforest ecosystems across the globe by preventing this nutrient rich dust from migrating across the Atlantic, in turn undermining the objectives of these projects.
The value of Saharan dust in places as unexpected as the Amazon Rainforest provide a couple more generalizable lessons relevant to scaling up any CDR approach:
1. Diversification of CDR approaches is important. It is unlikely that we will be able to simply plant a giant forest or rely on a single technology to remove enough carbon from the atmosphere to prevent climate change. The amount of carbon we need to remove from the atmosphere is simply massive, and would require significant transformation of ecosystems (with the accompanying unintended consequences). Any claims that a single CDR approach is the "silver bullet" for fighting climate change should thus be met with extreme skepticism...
2. We should accelerate the pace of carbon cycle and ecosystem research. Initiatives like the Global Carbon Project are a great start to understanding how to enhance natural carbon sinks with the fewest adverse consequences. Better understanding such ecosystem dynamics today is critical for evaluating which CDR approaches to pursue for development. And as an added benefit, further research into carbon cycles might also uncover novel CDR approaches that we can add to the portfolio of solutions necessary to combat climate change.