How are natural disasters and climate change related?
It is becoming increasingly clear that many disasters such as floods, storms, landslides and droughts are no longer purely natural, but are the most dramatic impacts of climate change caused by human activity. The world is now 1.2 degrees Celsius warmer than in pre-industrial times. With the UN calculating that current emission-control pledges will lead to a 2.7-degree warmer world by 2100, the frequency and intensity of such disasters is expected to increase.
There are two kinds of ‘natural’ disasters – fast and slow. Fast disasters include storms, floods, landslides and heatwaves, and have sudden and obvious effects. With slow disasters such as droughts, increases in water and soil salinity and crop losses, the impacts may take longer to emerge but they can be very severe. As far back as 2012, the Intergovernmental Panel on Climate Change (IPCC) established that all these disasters are increasing in frequency and intensity due to climate change.
The accuracy of that observation has been reconfirmed time and again in the past decade in South Asia and the Himalayas. Disrupted monsoons, increased salinity in coastal regions due to rising sea levels, and flash floods caused by faster melting of glaciers are just some of the ‘natural’ disasters that have been made more likely and more severe by human-induced climate change.
Cyclones more powerful due to climate change
In the past few years, cyclones in the Bay of Bengal have suddenly picked up intensity when they move over the sea. Scientists attribute this to the higher-than-before sea surface temperature, a result of climate change. This means more water evaporates and gets sucked into the vortex of the storm, making the cyclone more destructive.
How does climate change lead to floods in South Asia?
In 2020, scientists at the Indian Institute of Tropical Meteorology forecast that climate change would make the South Asian monsoon more erratic than before. That was borne out within a year: there were many rainless days during the 2021 June-September monsoon, punctuated by bouts of heavy rainfall in the plains and cloudbursts in the Himalayas. The result was a cycle of droughts and floods in quick succession, sometimes even in the same area. The Bundelkhand region, along the southern border of the Indo-Gangetic plains, is one example.
Floods in Assam and Bihar have become such a regular phenomenon that they no longer get the media coverage they should. They have been worsened not only by climate change, but also by poorly planned flood-control measures such as dams and embankments.
How does climate change lead to landslides in the Himalayas?
In the Himalayas, cloudbursts almost invariably lead to flash floods and landslides. In this, the youngest mountain range in the world, hill slopes are already less stable than in other ranges, and they have a higher percentage of loose soil. The slopes have been made even more unstable by construction of dams and poorly planned roadbuilding projects. The number of landslides in 2021 has been too high to track, in terms of incidents, fatalities and economic damage.
Cloudbursts and landslides are now occurring in the Himalayan region right from the start of the monsoon season, as happened in Nepal’s Melamchi river basin in 2021.
What is a GLOF?
A glacial lake outburst flood (GLOF) happens when water in a glacial lake – formed by water that has melted from a glacier – bursts its banks.
Different kinds of GLOFs are occurring in the Himalayas, their frequency increased by climate change. Lakes created by water from melting glaciers are bursting their banks, as happened in the 2013 Uttarakhand disaster. Entire ice walls are collapsing into rivers, as in the devastating flood in February 2021 in another part of Uttarakhand. Elsewhere, glacier ice sheets are sliding over meltwater, with an alarming example in northern Pakistan in May 2021. These incidents all lead to flash floods, causing huge damage.
How are forest fires related to climate change?
Another impact of climate change is drier forests, which is leading to more frequent and more intense forest fires from Canada to California, Spain, Greece, Siberia and Australia. South Asia is no exception. There is still inadequate media coverage of this rising threat in the region.
Forest fires also add to global warming in two ways. Burning forests release carbon dioxide – the main greenhouse gas warming the Earth’s atmosphere. Then, trees that have been burnt are no longer available to pull carbon dioxide from the atmosphere through photosynthesis, meaning forest fires can destroy one our most valuable carbon sinks.
Climate change worsens droughts
In 2021, up until the end of June, Central Asia suffered its worst drought in 13 years. The situation has since eased, but the threat remains – in Central Asia and around the world.
Monique Barbut, former head of the UN Convention to Combat Desertification, has said illegal immigrants to Europe from Africa and the Middle East are drought victims.
Climate change is making coastal areas more saline
Like drought, another huge impact of climate change that creeps up on people is the salinity of surface water and groundwater along coasts. As sea levels rise due to climate change, tides bring saltwater further inland, contaminating freshwater ponds and turning river water saline further and further upstream.
At the same time, saltwater driven by rising sea levels is intruding into aquifers. People with no choice but to drink increasingly saline water suffer serious health impacts, and the increased salinity of the soil can make growing crops impossible. The Third Pole has reported on these trends in Bangladesh, India and Pakistan.
Management of disasters
Policymakers around the world are becoming aware that they cannot prevent climate change-related disasters; the best they can do is to manage and prepare for them. Various ways to do so have been suggested by experts at the UN Office for Disaster Risk Reduction, and some have been used successfully. For example, heatwave warnings are becoming routine in South Asia. Examples in the Himalayas include flood early warning systems. Deaths from cyclones have been reduced drastically thanks to meteorologists who are now able to forecast storm tracks with a high degree of accuracy. But there is an urgent need to create warning systems for landslides and forest fires.
How do we know about the links between climate change and disasters?
In the past decade, a new academic discipline has been established: attribution science. Scientists are now looking at specific disasters to determine the connection with climate change. The discipline has made such rapid progress that two of its pioneers are on the Time magazine list of the 100 most influential people in the world in 2021. The latest IPCC report cites several studies that can attribute a direct link between climate change and disasters.
One of the earliest attribution studies was of the May 2015 heatwave in the Indian states of Andhra Pradesh and Telangana, when around 2,500 people died. After the study, scientists calculated that climate change had made a similar heatwave 10 times more likely than before.