We know some things that we got wrong. We saw climate change coming, generations ahead. Could a time traveller change a damned thing? Probably not! Unless t

We know some things that we got wrong. We saw climate change coming, generations ahead. Could a time traveller change a damned thing? Probably not! Unless they had some brilliant tech, say,chemistry for excellent batteries and solar panels that could have been made with 50s tech -- that might have put us on a different trajectory altogether.