Mercury is a potent toxin that interferes with the human nervous system. Reducing this hazard will be a major public health breakthrough.
A cap on carbon is important because it sets a specific goal for reducing carbon emissions 80% by 2050.
Pollution from human activities is changing the Earth's climate. We see the damage that a disrupted climate can do: on our coasts, our farms, forests, mountains, and cities. Those impacts will grow more severe unless we start reducing global warming pollution now.