An international group of researchers has plotted the different ways on one table to drive home the urgency of the climate change crisis.
Bengaluru: A world trying to hold it together amid unprecedented chaos, it’s a pure dystopian nightmare: Multiple natural disasters causing widespread death and destruction. The constant shocks of a changing climate breeding hostility in the household as well as geopolitics. Increasingly polluted cities causing more and more children to be born with development impediments.
Greenhouse gas emissions impact humanity and the Earth on multiple levels. But because the effects are gradual, the alarm with which they need to be perceived is dampened considerably.
A study published in the journal Nature Climate Change delves into past studies that outline effects of emissions on the climate, and traces a shocking 467 pathways through which humanity has already been affected. The idea is to inject a sense of urgency in the approach to climate change by highlighting the several likely hazards all at once.
The study lists the effects the changing climate has had on human health, water, food, economy, infrastructure, and security, through hazards like heatwaves, droughts, floods, fires, storms, sea-level rise, changes in natural land cover, and oceanic chemistry.
Conducted by researchers from the US along with collaborators from the UK, Sweden and Japan, the study paints an ominous picture: Even if the current levels of emissions are drastically curbed by 2100, different parts of the world would be exposed concurrently to a disaster like floods, heatwaves, droughts or fires on an unprecedented scale. If they aren’t, as many as three are likely to coincide, with “some tropical coastal areas facing up to six simultaneous hazards”.
How the study was conducted
The team of researchers dipped into the large body of studies published so far about the different types of impact climate change has had on people.
Various combinations of the above-mentioned terms and their associated keywords were used to search through nearly 12,000 research papers, of which 3,280 were used in this study. The studies selected all showed the observable impact with traceable evidence from the last 40 years.
“So many studies look at how individual climate hazards will change in the future, but none of them consider all of the variables together,” Abby Frazier, one of the authors of the study and a climate scientist at the East-West Center at University of Hawai‘i, Mānoa, told ThePrint. “This paints an unrealistic picture of the future and underestimates the consequences that climate change will have on humanity.”
The researchers created a table with 10 climate change hazards in columns (warming, precipitation, floods, drought, heatwaves, fires, sea level, storms, changes in natural land cover, and ocean chemistry) and six aspects of human systems (health, food, water, infrastructure, economy and security) in rows, to trace how each is linked.
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How climate change has affected us so far
First, there are the observable effects.
Extreme weather events cause direct deaths. The 1998 China floods killed 3,000 people; the 1980s drought in Ethiopia led to the death of 800,000; the 1991 Cyclone Gorky in Bangladesh killed 140,000; and the 2004 tsunami left nearly 230,000 people dead.
Increased greenhouses gas emissions cause direct damage to human health in the form of respiratory disorders, cardiac issues, developmental problems in children, and more.
Exposure of pregnant women to fires and smoke, and regular air pollution, causes babies to be born underweight, and entails incomplete mental development and bad academic performance.
Then there are the slightly more indirect impacts that are obvious to the experts but difficult for the layperson to observe.
Increased warming can cause increased evaporation, leading to dryness. Such weather conditions are ideal for wildfires and heatwaves, as the US state of California has come to discover. Increased evaporation boosts precipitation, and incessant rains lead to frequent floods. Additional levels of carbon dioxide in the atmosphere mix with the top layer of water in the oceans, forming carbonic acid, leading to a process called ‘ocean acidification’ that imperils marine life.
According to the researchers, catastrophic events like floods have brought animals and humans into proximity, and this has increased the spread of disease and conflicts like snake bites. Melting permafrost, they said, has been known to release decades-old disease carriers, causing scary outbreaks we aren’t prepared for, while poor sanitation after a natural disaster is a factor in outbreaks of diseases such as tuberculosis, malaria, and dysentry.
Increased arid conditions have led to more forest fires, which have brought fauna closer to humanity, another possible cause for the spread of diseases (outbreaks of the Hendra and Nipah viruses are both linked to fruit bats moving closer to towns because of forest fragmentation), the researchers noted.
Changes in ocean chemistry caused changes in the chemistry of the plants that grow in the sea, with harmful algal blooms resulting in seafood poisoning and cholera.
Increasing sea levels have brought salt water into drinking water storage spaces, causing illnesses like gestational hypertension in pregnant women.
Possible impact on mental health
Mental health is often affected as well. There has been an increase in the incidence of depression and post-traumatic stress disorder (PTSD) after storms and floods in the US, the UK, and France.
Loss of sea ice has disturbed cultural practices such as hunting and fishing among the Inuit community, again causing depression. The weather also affects daily human behaviour. Increased temperatures are believed to cause irritability and anger, leading to tense and volatile interpersonal relationships that can then result in violence and crime, disproportionately against women.
Crops that sustain a large population not only suffer direct damage from events like floods and fires, but also increase in temperatures, which can then harm the economy.
For example, wheat suffers a 3-10 per cent loss of yield for each degree that temperature rises. Heatwaves, droughts, and fires in the summer of 2010 in Russia decreased the production of wheat by a third, causing global wheat prices to almost double. Russia is the world’s largest wheat exporter.
Loss of crops is a crisis for farmers, and a study suggested that temperature fluctuations in the growing season were linked to farmer suicides in our country.
High ocean temperatures affect fish, leading to fragile prospects for fishermen. Job losses are regularly reported in parts of the world, including India, where excessive heatwaves cause employees to take days off, which also hampers productivity.
Heatwaves have also had drastic effects on infrastructure. The asphalt on roads melts, requiring repair, flights are frequently grounded as hot air is less dense than cold air and is an impediment to flying, and power lines expand, sag, and short out on trees.
Excessive heat increases power consumption, causing power blackouts and affecting urban productivity. Tourism suffers everywhere, as it is heavily reliant on weather (skiing, scuba diving, etc).
Floods and storms destroy millions of homes, leaving billions of dollars of damage in their wake. There are larger implications too: For example, Hurricane Katrina damaged oil rigs, reportedly causing an increase in fuel prices in the US for over a decade.
In developing countries like Bangladesh, regular flooding events cause rural settlements to move closer to the cities, which leads to the proliferation of slums.
Droughts, it is feared, may trigger violent water conflicts. Changes in rainfall patterns reduced availability of suitable land for agriculture, leading to a hunger crisis in the Horn of Africa. It has also often been pointed out that the Syrian civil war was preceded by an excruciating drought.
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What next?
Estimates for 2100 based on current data point to different parts of the world suffering simultaneous exposure to multiple climate hazards.
Europe and the Americas are set to have intense droughts, while Asia will see more floods, and Australia more fires. The incidence of heatwaves and extreme rains will increase in the tropics, and that of water scarcity in Africa.
However, the researchers said, understanding the inevitability of destruction is dampening, but shouldn’t prevent efforts towards mitigation.
“The worst we can do is do nothing,” said Frazier.
“If we act now, we can reduce the magnitude of the effects, which will make a huge difference down the line,” she added. “Even the difference between the impacts under 1.5° warming and 2° warming is incredible, and we should be doing everything in our power to avoid reaching that 2° mark.”
“We need to substantially reduce greenhouse gas emissions, reduce fossil fuel subsidies, diversify our energy matrix, and provide financial incentives and regulations for improved land management in the agricultural sector.”