The report, commissioned by Congress, warned against Donald Trump’s direction on climate action and pro fossil-fuel agenda, saying “future risks” were dependent on “decisions made today”.
It warned the effects of greenhouse gas emissions, including storms, droughts and flowing, could impact on a range of services in the US, including health and infrastructure. This damage was likely to cost the US economy billions, the report carried out by the government agency US Global Change Research Programme, said.
With emissions at “historic rates”, annual losses in some economic sectors are projected to “reach hundreds of billions of dollars by the end of the century”, the Fourth National Climate Assessment Volume II report said. This is more than the current GDP of many states in the US, it added.
The study added that the projects could change if greenhouse gas emissions were reduced, although many of the impacts of climate change were already happening, it noted.
“Future risks from climate change depend primarily on decisions made today,” it said.
“Earth’s climate is now changing faster than at any point in the history of modern civilisation, primarily as a result of human activities.
“The impacts of global climate change are already being felt in the US and are projected to intensify in the future—but the severity of future impacts will depend largely on actions taken to reduce greenhouse gas emissions and to adapt to the changes that will occur.”
The report, which was conducted with the help of dozens of US government agencies and departments, projected that global warming could disproportionately affect the poor, create health problems, damage infrastructure, limit the access to water, change coastlines and have a negative impact on sectors such as farming, fishing and energy production.
The report supplements a study issued last year that concluded humans were the main cause of global warming.
Both studies appear to undermine Trump’s repeated assertion that climate change is not worsened by the actions of people.
He has encouraged the burning of coal and increase of greenhouse gas pollution. He has also announced the US will pull out of the Paris Agreement.
According to the terms of the agreement, the US can not effectively withdraw before November 4 2020.
A White House statement said in response to the report that is was “largely based on the most extreme scenario, which contradicts long-established trends by assuming that… there would be limited technology and innovation, and a rapidly expanding population”.
It also said the next National Climate Assessment gives the government the “opportunity to provide for a more transparent and data-driven process” for greater balance.
The federal government is required to issue the climate assessment every four years.
