Just reading about the CDR enhancements in en-ROADS. The idea of crushing minerals and spreading them on beaches and fields leave me wondering about the ecosystem impact of that. Sounds like potentially a very bad idea at scale.

Really important to include Biodiversity and ecosystem considerations included.

Any thoughts?

The papers covering mineralization tend to mention environmental and health risks only as something that can be avoided or limited. We think their major shortcoming is failing to recognize the scale of what is being proposed, which is why we added the plot of bulk materials compared to the coal industry. We do not plot the fertilizer industry - which might be interesting given that the discussion is about spreading on fields - because it is so much smaller than the material needed for enhanced mineralization it would be barely visible on the graph. Protecting ecosystems and the health of workers would both have to be part of the design of an intervention like this.

That said, if material is being spread on farmland, there is probably low risk of impacting biodiversity any more than farming already does through land use. And the amount of material is vast in total, but is really just a dusting - the default 34 tons per Ha per year is about 3mm thick (at 1500 kg/m3 when ground like sand). And for some soils, rock dust can help counteract acidity caused by past farm practices, creating a side benefit. An overall industry that size is probably a bigger impact than the effect of spreading dust on particular pieces of land.

Biodiversity is not modeled in En-ROADS, but we try to give some indicators that might help you discuss it - like the area and material required. So especially when participants are counting on solutions besides keeping fossil fuels safely underground, you should try to get them to uncover what might be the ecosystem, health, and justice impacts, both positive and negative, and how to design each policy to multisolve.