A report from the Intergovernmental Panel on Climate Change finds "human interference with the climate system" could lead to strains on food systems and conflicts over natural resources like water.
Kerry said in a statement that mankind's way of life is in jeopardy because of the threats from climate change.
"There are those who say we can’t afford to act," he said. "But waiting is truly unaffordable. The costs of inaction are catastrophic."
The IPCC report says everything from rising temperatures to flooding and landslides may be connected to the increased level of carbon dioxide in the atmosphere, which is linked to the consumption of fossil fuels.
Vincente Barros, a co-chair of the working group that drafted the report, said many of the risks come from a lack of action.
"We live in an era of man-made climate change," he said. "In many cases, we are not prepared for the climate-related risks that we already face."
The report's authors lament that most policymakers are reacting to past events triggered by climate change rather than preparing for a changing climate future.