Every summer there are some who die of heat stroke. Yes, there are survivors, but that doesn’t mean the heat isn’t dangerous; it just means you’ve decided you’re comfortable with what you perceive to be a low risk. But each summer that heat stroke death toll will get higher. What happens when you decide you’re no longer comfortable with the risk? By then we will have missed several key opportunities in reducing CO2 levels. Better to stem the tide now, no?