I don't know, but disrupting an ecosystem has knock-on effects. It could change something else much more directly important to humanity. That is a big premise

I don't know, but disrupting an ecosystem has knock-on effects. It could change something else much more directly important to humanity. That is a big premise of climate change mitigation. We don't necessarily know all the knock on effects of CO2 and other pollution, but we don't need to. Any climate/ecosystem alteration is generally disruptive to civilization, which is why things have to be so critical to even discuss geoengineering.