For Days 14 through 25 of 28 brainstorming signs for the People’s Climate March, I tried to focus especially on the self-reinforcing cycles and feedback loops of climate change. The tendency of climate change to reinforce itself once it gets started is one of the most frightening things about this challenge. The biggest of these climate change feedback loops is pretty well known– increased heat melts the polar ice caps, without the reflective white of polar ice, more heat is absorbed, raising temperatures even further. At the same time, permafrost in polar regions also melts, releasing methane and CO2 that has been trapped for millennia into the atmosphere, and increasing greenhouse gas emissions, further accelerating the heat-trapping greenhouse effect. The possibility that incremental warming could lead to extensive and accelerating warming is something we need to look at realistically, because we are on the precipice of kicking this (and many other) feedback loops into overdrive. In California we are already seeing some of these feedback loops (specifically the one related to tree death due to climate change and drought) play out. I was so honored to hear that someone from Yosemite had taken a sign inspired by the tree feedback loop (above, and on the web if you an email subscriber) to the Yosemite March for Science. We need to raise awareness about the urgency of the moment we are in, and I think building and understanding of the feedback loops can play an important part in that.