The increase of simultaneous natural disasters caused by climate change over the next century will be devastating for human society, according to a new study.
A team of researchers picked through thousands of scientific papers and found 467 different ways greenhouse gasses affect human health, food, water, economy, infrastructure, and security.
As emissions increase, society faces a much larger threat from climate change than previously thought, the team from University of Hawaii in Manoa said.
Greenhouse gas emissions can simultaneously cause hazards to human life including warming, drought, heatwaves, wildfires, precipitation, floods, storms, sea level rise and changes in land cover and ocean chemistry.
As a result of emissions increasing atmospheric temperatures, soil water evaporation also increases and causes drought, wildfires and heatwaves in normally dry places – or massive rain and floods in commonly wet areas.
In the oceans, warmer waters also evaporate faster, increasing wind speeds and the downpours of hurricanes, whose surges can be aggravated by sea level rise.
The increasing exposure to the multitude of climate hazards will impact both rich and poor countries – especially in tropical coastal areas.
In the year 2100, New York is expected to face up to four climate hazards, if greenhouse gas emissions are not mitigated.
Sydney and Los Angeles will face three concurrent climate hazards, Mexico City will face four, and the Atlantic coast of Brazil will face five.
The study was co-authored by 23 scientists, including several who are on the Intergovernmental Panel on Climate Change and they have released an interactive map of the threats.
For example by 2095 the UK faces increased warming, rainfall and drought while suffering a deficit in fresh water.
The paper concludes urgently: “Overall, our analysis shows that ongoing climate change will pose a heightened threat to humanity that will be greatly aggravated if substantial and timely reductions of greenhouse gas emissions are not achieved.”
Lead author Associate Professor Camilo Mora said: “Greenhouse gas emissions pose a broad threat to humanity by simultaneously intensifying many hazards that have proven harmful in the past.
“Further, we predict that by 2100 the number of hazards occurring concurrently will increase, making it even more difficult for people to cope.
“The collision of cumulative climate hazards is not something on the horizon, it is already here.
“Co-occurring and colliding climate hazards are already making headlines worldwide.
“Last year, for instance, Florida recorded extreme drought, record high temperatures, over 100 wildfires, and the strongest ever recorded hurricane in its Panhandle: the category 4 Hurricane Michael.
“Likewise, California is currently experiencing ferocious wild fires and one of the longest droughts, plus extreme heatwaves this past summer.”
Dawn Wright, ESRI Chief Scientist said: “The study is a compelling review of how climate change is literally redrawing lines on the map, clearly showing the threats that our world faces at every level.
“The maps and data hammer home how much danger humanity truly faces, and the need for immediate action,” said
Co-author Professor Jonathan Patz, from the University of Wisconsin’s Global Health Institute said: “Our health depends on multiple factors, from clean air and water, to safe food and shelter and more.
“So without a real systems approach to climate change impacts, we cannot adequately understand the full risks.
“If we only consider the most direct threats from climate change, for example heatwaves or severe storms, we inevitably will be blindsided by even larger threats that, in combination, can have even broader societal impacts.”
Co-author Assistant Professor Daniele Spirandelli from the University of Hawaii said: “The evidence of climate change impacting humanity is abundant, loud and clear.
“Clearly, the outstanding question is – how many wake-up calls will it take to wake up?”
The study was published in the journal Nature Climate Change.
By Adela Whittingham
