I would change the human brain. Thanks to millions of years evolving in small groups on the savannah, our brains are rather maladapted to being part of a single human tribe of billions, most of whom we will never see or know, with collective effects on our global habitat that play out incrementally over centuries and are irreversible and possibly unadaptable.
Because we spent millions of years as creatures whose lives were short and brutal, we are designed to recognize threats with faces—proximate threats that we can see and touch and smell, that affect our own families and social groups. We have a great deal of intellectual difficulty understanding threats like climate change, where the cumulative effects of our actions today shape the lives of people far away or not yet born. But we have even more difficulty translating that somewhat abstract knowledge into motivation for action.
Today, we are on a course that is likely to render our planet unsuitable for human civilization—if not by 2100, by 2300
David Roberts is a staff writer at Grist.org.