The recently released report cites wide and severe impacts: more sea-level rise, flooding, storm surges, precipitation and heat waves in the Northeast; frequent water shortages and hurricanes in the Southeast and the Caribbean; and more drought and wildfires in the Southwest, the Washington Post reported.
Temperatures at sea, on land and on ice all point to a warming trend over the past century, according to several indicators in the government's National Climate Assessment.
Katharine Hayhoe, a Texas Tech University professor and a co-author of the report said that for a long time, it was perceived climate change as an issue that's distant, affecting just polar bears or something that matters to our kids, but this shows it's not just in the future; it matters today, and many people are feeling the effects.
The federal climate assessment - the third since 2000 - brought together hundreds of experts in academia and government to guide US policy based on the best available climate science.
The authors of the more-than-800-page report said it aims to present "actionable science" and a road map for local leaders and average citizens to mitigate carbon and other gas emissions that warm the planet.
Burning coal for electricity, using gasoline to fuel vehicles, clear-cutting forests and engaging in certain agricultural practices that remove carbon-trapping vegetation contribute to the problem, the assessment said.
By the end of the century, temperatures could be up to 5 degrees higher, even if the nation acts aggressively to reduce greenhouse gas emissions. It could be up to 10 degrees hotter if emissions are high.
The higher the temperature, the more dire the impact. Extreme weather in the United States caused by climate change has increased in recent decades, the report said.
The decade starting in 2000 was the hottest on record, and 2012, the year Hurricane Sandy followed an epic summer drought, was the hottest ever recorded in the nation's history, the report added.