Shonil Bhagwat, The Open University

It looks like Donald Trump’s “great, great wall” is actually going to happen. Its likely impact on human society has been well-noted, but in the longer-term a barrier across an entire continent will also have severe ecological consequences.

The US-Mexico border is around 1,900 miles (3,100 km) long and some of it has already been fenced off. According to Trump the proposed wall will cover approximately 1,000 miles and “natural obstacles” such as rivers or mountains will take care of the rest.

Aside from the debates over whether or not the wall will do much to stop drug trafficking or illegal immigration, how much it will cost the US taxpayer, or whether Mexico will pay for it, a 1,000-mile wall has significant environmental costs. For a start, all that concrete will generate millions of tons of carbon dioxide emissions. And then you have…