Global warming is caused by human activity and failure to address it will cost the US dearly. That鈥檚 the uncompromising message from a draft of a major US report on climate science.
The full report is due to be published in the spring by the , a body charged by Congress with assessing climatic impacts on the US every four years. But some of the report鈥檚 contents are now public, because it has been reviewed by a committee of the . and they suggest the government report will pull no punches in detailing the threats posed by climate change.
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That message might not go down well in the White House. President Trump has previously suggested global warming is a concept 鈥渃reated by and for the Chinese鈥�.
Almost no one in the scientific community doubts that climate change is a threat to civilisation, and is largely caused by human activity. But because of Trump鈥檚 views, scientists have expressed fears that .
So far, though, it does not seem to be happening.
Climate of fear
In November the US Global Change Research Program , on the causes of climate change.
The report concluded that it is 鈥渆xtremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century鈥�. One of the authors, at the NOAA Earth System Research Laboratory in Boulder, Colorado, said he was confident there had been 鈥渘o political interference鈥�.
Some insiders speculated that the White House chose to publish the November report, despite its Trump-unfriendly conclusions, because draft versions had been publicly released months earlier 鈥� so any attempts to water it down would have been obvious.
Volume two of NCA4 may also be published with no political interference, if the review is anything to go by. The review, chaired by of Columbia University in New York, is a chapter-by-chapter assessment. It contains little to suggest the text has been altered for political expediency.
The reviewers鈥� only real criticism is of the report鈥檚 writing style. They say the key message sections are overstuffed with science, and need pithy messages summarizing the likely impacts.
Still, the text does not hold back.
Scary prospects
鈥淐limate change under a high-emissions scenario without adaptation will impose substantial physical and economic damages on the United States economy, human health and the environment, with the potential for annual losses in some sectors reaching hundreds of billions of dollars by the end of the century,鈥� warns the report. 鈥淪ome impacts, such as sea level rise from ice sheet disintegration, will be irreversible for thousands of years, while others, such as species extinction, will be permanent.鈥�
Many of the worst impacts could be eased, says the report, if the US backed the Paris Agreement signed in December 2015 to limit the rise in global temperature to 2掳C by the turn of the century. Trump plans to withdraw the US from the agreement.
鈥淏y the end of this century, reducing the severity of climate change by reducing greenhouse gas emissions could save thousands of lives each year and produce hundreds of billions of dollars in health-related economic benefits each year, compared with following a pathway of higher greenhouse gas emissions,鈥� the report says.
By instead allowing the release of still more carbon dioxide, by promoting the burning of coal for energy, Trump may deny the US these benefits and harm Americans鈥� health.
Bad for us
鈥淐limate change is increasing the risk of adverse respiratory and cardiovascular effects, including premature death, due to higher concentrations of air pollutants in many parts of the United States,鈥� the report says.
Projected increases in wildfires could cause lung problems, the report warns. It notes that since the 1970s, the frequency of large forest fires has increased by 1000 per cent in the Northwest US, and by 889 per cent in the Northern Rocky Mountains.
Increasing floods also threaten chaos. 鈥淓xtreme precipitation events are projected to increase in a warming climate and may lead to more severe floods and greater risk of infrastructure failure in some regions,鈥� the report warns.
And in Hawaii, fish stocks may dwindle because of damage to coral reefs. 鈥淏leaching and acidification will result in loss of reef structure, leading to lower fisheries yields and loss of coastal protection and habitat,鈥� says the report. 鈥淒eclines in oceanic fishery productivity of up to 15 and 50 per cent respectively of current levels are projected by mid-century and 2100.鈥�
