In the past two decades, there have been more daily records set for highs than for lows across all regions of the United States.
An estimated 5,000 gathered in Denver's Civic Center Park as Michael Hancock, Wellington Webb and others offered endorsements.
Seven states have been working for years on drought contingency plans. Arizona and California have missed two deadlines.
If the United States reduces carbon emissions before 2080, the trajectory would slow, but not stop.
The 75-year-old Gian-Franco Kasper spoke of "so-called climate change" and said he would rather deal with dictators than argue with environmentalists.
Climate change and deforestation are the leading causes responsible.
Women are more likely than men to be killed in natural disasters, and more likely to become refugees after drought and famine.
Environmentalists and oil companies have been on edge since the Supreme Court heard oral arguments in the fall.
Colorado's hot summer days are spilling out of their regular timeframe. They are starting earlier (June) and staying later (September).