I keep hypothesizing that using a website or software to somehow promote pedestrianism would be helpful. You don't even need to promote it as <i>fighting climate change</i> per se. You could promote it as <i>how to save money on gas while improving your personal fitness.</i><p>There are probably other creative approaches. But I would try to think about what's their motivation. What is in it for them. Moralizing tends to not have the best track record for promoting the changes we would like to see. It tends to just force "bad behavior" underground, which can lead to worse things.
Bret Victor wrote an essay in 2015, "What can a technologist do about climate change?" - <a href="http://worrydream.com/ClimateChange/" rel="nofollow">http://worrydream.com/ClimateChange/</a>
Spreading awareness would be good. Many people reject the notion that the climate is changing, so there would be value in collating the most persuasive and concrete arguments.<p>It's important to filter out conjecture and anecdata, though.
habitrpg like carbon footprint reduction app. And/or a "pyramid scheme" where you could challenge friends to participate and get credit for onboarding people and their reductions.
if you could optimize the traffic lights in cities, you could save a ton on gas. All the stopping and going due to hard coded timers wastes a ton and creates more pollution.