A phone app by the US government where people earn points/likes and people can trade those points in for rewards. A similar system exists now between grocery stores and gas stations.
The Giant grocery store chain has a partnership with Shell gas stations where for every $10 you spend at giant, you get $0.10 off at the pump at Shell gas stations. It's all kept track through the Giant app which transfers over to the Fuel Rewards app. Safeway grocery stores and Exxon do something similar. Most people these days have smart phones, and psychologically, people respond to earning points/rewards/likes.
If the US government could make an app where US citizens (or maybe it can be more than just Americans) can acquire points or likes for doing something (like solar power usage, turning down your AC or heat during peak times, volunteering, picking up litter, driving electric cars, not using plastic bags, climate change related stuff, healthy living like points for going to doctors appointments or ordering the healthy thing at restaurants) and those points and likes can be traded-in for rewards sponsored by the government.
People can trade the points in for extra food or food stamps, tax breaks with the IRS, maybe some partnership with other companies, etc. This can help people that are very poor (that have a smart phone) to those that are really rich. And this could scale up. If the government likes what a city or state has done policywise or some accomplishment, everyone that's a resident of that city or state can be rewarded credits/points/likes for trade-in use. People also like to be recognized. Maybe this can be connected to social media if people opted in for that.
This program could be a way to address big issues like climate change, pollution, hunger, and energy and would circumvent the need for laws being passed by a Congress. This could start as a small program in a city and then be adopted on a federal level. I think people would really get behind this as people like getting rewarded for not having to do a lot. And some will see this as a version of 'extreme couponing'. And maybe this can be a nudge for people to do things that are positive for the community or the world.