There are many programs and projects that need support...
ClimateDonor.org sources projects from nonprofits, universities, national labs, and local government agencies in a "one-stop-shop" portal so that individual donors can contribute to initiatives that are important to them.
It might be a permaculture garden in their neighborhood, a wetlands restoration project, an alternative energy project for their city, a home energy audit and remediation program in a low income neighborhood, creating a prototype from university research, clean energy projects for a school, more sustainable farming projects, or providing solar powered lighting for schools in developing countries.
The goal is to drive more grassroots citizen awareness and engagement, while providing funding to a wide variety of projects that might not otherwise get the funds they need. In aggregate these projects can have a material impact on addressing climate change and help drive awareness and foster sustainable lifestyles.