Climate Change
Highlights
- Severe floods in Kentucky, USA
- rapid changes in the water cycle
- impact of climate change
Climate Change: In late July, flash floods caused by a powerful storm system occurred across parts of the United States. This led to record rain inundating areas around Lent Louis and causing landslides in eastern Kentucky. At least 16 people died in this flood. In another disaster, the Las Vegas area of Nevada was also submerged in floods. Due to climate change, such water disaster incidents are now coming to the fore. A powerful storm in the US was followed by severe flooding in India and Australia this summer, compared to the same situation in Western Europe last year.
Studies conducted by scientists from all over the world have revealed that the water cycle is taking a fierce form and its intensity will increase as the planet warms. I was a co-author of the International Climate Assessment Report prepared in 2021 for the Intergovernmental Committee on Climate Change, which gives detailed information on this topic. It has documented both harsh climates, with heavy rainfall in most areas and severe drought-prone areas such as the Mediterranean region, South West Australia, South West, South America, South Africa. The report also shows that the intensity of rain and drought will increase as global temperatures rise.
How is the water cycle formed?
The water cycle is formed by the movement of water between the atmosphere, ocean, land, reservoir and frozen ice. It can fall from the atmosphere to the earth in the form of rain or snowfall, can be absorbed by the land and flow into rivers and reservoirs, mix into the sea, can freeze and return to the atmosphere through evaporation. Trees and plants also absorb water from the soil and expel it through the leaves like sweat. Overall the rate of both condensation and evaporation has increased in recent decades. There are many reasons for the severe water cycle, but the most important is the increase in temperature, which raises the upper limit of the amount of moisture in the air. This also increases the potential for further rain.
This aspect of climate change is confirmed in all our lines discussed in the IPCC report. Similar results are expected in the prediction of computer models, a fundamental principle of physics. Monitoring data is also already showing that the intensity of rain is increasing with increase in temperature. Understanding this and other changes in the water cycle is more important than preparing for disaster. Water is a vital resource for all ecosystems and human society, especially for agriculture. Exacerbation of the water cycle means that there is an increase in the rate of severe floods and drought and the same difference between the water cycle. However, it will not be uniform across the world.
Drought can come in many parts
Severe rain is expected to extend over most areas, but the Mediterranean region, the Southwest, South America and large parts of western North America are expected to be hit by severe drought. Globally, every one degree Celsius temperature rise in the world is expected to increase the rate of daily massive condensation by seven percent. According to the report, other aspects of the water cycle will change with the increase in global temperature, including reduction in glaciers on the mountains, reduction in the duration of snow cover of areas according to the season, early snow melt, conflicting monsoon in different regions. Changes are involved, which will affect the water resources of millions of people.
There is a common ‘theme’ to these aspects of the water cycle that the more greenhouse gas emissions, the greater the impact. The IPCC does not make a policy recommendation. Instead, it provides scientific information, which needs to be carefully evaluated for policy making. A scientific piece of evidence included in the report explicitly tells world leaders that an urgent need to limit global temperature rise to 1.5 degrees under the Paris Agreement, accelerate and massively reduce greenhouse gas emissions. Beyond any specific target, it is clear that the serious effects of climate change are directly linked to greenhouse gas emissions. Reduction in emissions will reduce the impact (negative). Even a tiny fraction of each degree matters.
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