Strong Storm Systems Hitting Northeastern US From July 9, 2023, Dismissed close to 10 inches of rain in New York's Lower Hudson Valley in less than a day and sent mountain rivers overflowing their banks and in cities beyond Vermont. Vermont Gov. Phil Scott said he had not seen such rainfall since Hurricane Irene devastated the area in 2011.
Extreme marine disasters like this have disrupted lives in countries around the world in recent years, from the Alps and West Europe to Pakistan, India and Australiaalong with several US states in 2022 and 2023.
The role of climate change is becoming increasingly apparent in these types of floods.
US Military Academy via AP
Studies by scientists around the world show that the water cycle has intensified and will continue to intensify as the planet warms. One international climate assessment I wrote 2021 for the Intergovernmental Panel on Climate Change, reviewed the research and presented the details.
It documented an increase in both wet extremes, including heavier rainfall in most regions, and dry extremes, including drought in the Mediterranean, southwestern Australia, southwestern South America, southern Africa, and western North America. It also shows that both wet and dry edges will continue to increase with future warming.
Why is the water cycle intensifying?
Water cycles through the environment, moving between the atmosphere, ocean, land and frozen water reservoirs. It can fall as rain or snow, seep into the ground, run into a waterway, join the ocean, freeze, or evaporate back into the atmosphere. In recent decades, there has been a overall rate increase of precipitation and evaporation.
A number of factors intensify the water cycle, but one of the most important is that warming temperatures increase the upper limit of the amount of moisture in the air. This increases the chance for more rain.
This aspect of climate change is confirmed to all all our proofs. It is expected by basic physics, projected by computer models, and already shows up in observational data as a general increase in rainfall intensity with increasing temperature.
Understanding this and other changes in the water cycle is important for more than disaster preparedness. Water is an essential resource for all ecosystems and human societies, especially agriculture.
What does this mean for the future?
An intensified water cycle means that both wet and dry extremes and the general variability of the water cycle will increase, although not uniformly across the globe.
The intensity of precipitation is expected to increase for most land areasbut the largest increases in dryness are expected in the Mediterranean, southwestern South America, and western North America.
IPCC Assessment Report Report
Globally, daily precipitation extremes will likely intensify by ca 7% for every 1 degree Celsius (1.8 degrees Fahrenheit) that global temperatures are rising.
Many other important aspects of the water cycle will also change In addition to extremes as global temperatures rise, the report shows, including declines in mountain glaciers, a reduction in the length of seasonal snow cover, earlier melting of snow and opposite changes in monsoon rainfall in different regions, that will affect the water resources of billions of people.
What can be done?
A common theme in these aspects of the water cycle is this Higher greenhouse gas emissions lead to greater impacts.
The IPCC does not make policy recommendations, but the results show what the potential effects of different options are.
One thing scientific evidence in the report clearly tells world leaders that limiting global warming to the international target of 1.5 C (2.7 F) will require immediate, rapid and large-scale reductions in greenhouse gas emissions.
As the evidence shows, every fraction of a degree matters.
This updates an article originally published on July 29, 2022, with flash flooding in the Northeast.
