The phrase "devastating consequences" means that something has caused very serious and harmful effects or outcomes, often resulting in great damage or harm. Full definition
If you're wondering why life insurance is important, stop to consider the potentially devastating consequences of not having coverage to financially protect the people that you love. (protective.com)
The reaction would likely delay effective emission reductions, so as to practically guarantee that climate would pass tipping points with devastating consequences for nature and humanity. (dotearth.blogs.nytimes.com)
With devastating consequences for the environment and the climate. (energypost.eu)