Another round of powerful atmospheric rivers is hitting California, following storms in January and February 2023 that dumped record amounts of snow. This time, the storms are warmer, and they are triggering flood warnings as they bring rain higher into the mountains – on top of the snowpack.
Professor Keith Musselman, who studies water and climate change at the University of Colorado’s Institute of Arctic and Alpine Research, explained the complex risks rain on snow creates and how they might change in a warming climate.
What happens when rain falls on snowpack?
For much of the United States, storms with heavy rainfall can coincide with seasonal snow cover. When that happens, the resulting runoff of water can be much greater than what is produced from rain or snowmelt alone. The combination has resulted in some of the nation’s most destructive and costly floods, including the 1996 Midwest floods and the 2017 flood that damaged California’s Oroville Dam.
Contrary to common belief, rainfall itself has limited energy to melt snow. Rather, it is the warm temperatures, strong winds and high humidity, which can transport substantial energy in the form of latent and sensible heat, that predominantly drive snowmelt during rain-on-snow events.
CNN reports that satellite photos show that the overflowing Indus has created a new body of water in southern Pakistan some 62 miles (100km) wide. It will take days or weeks for the water to recede, and in the meantime millions are left homeless and over all, 33 million people have been affected by the worst monsoon floods in recorded history. CNN quotes Pakistan’s Climate Minister Sherry Rahman as saying “That parts of the country ‘resemble a small ocean,’ and that ‘by the time this is over, we could well have one-quarter or one-third of Pakistan under water.’”
Because of our burning of fossil fuels to drive cars and heat and cool buildings, the world is heating up. But the Indian Ocean is heating up a third faster than the rest of the world. Very warm waters in the Bay of Bengal are helping create more destructive cyclones and flooding. The air over warming waters contains more moisture than the 20th century average. Warming waters also make the winds that blow over them more erratic, and wayward winds from the Arabian Sea helped push the heavy monsoon rains farther north than they usually extend.
The international report was led by scientists from the U.S. National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Environmental Information.
“The data presented in this report are clear — we continue to see more compelling scientific evidence that climate change has global impacts and shows no sign of slowing,” NOAA Administrator Rick Spinrad said in a statement. “With many communities hit with 1,000-year floods, exceptional drought, and historic heat this year, it shows that the climate crisis is not a future threat but something we must address today as we work to build a climate-ready nation — and world — that is resilient to climate-driven extremes.”
As global temperatures rise, desert climates have spread north by up to 100 kilometres in parts of Central Asia since the 1980s, a climate assessment reveals1.
The study, published on 27 May in Geophysical Research Letters, also found that over the past 35 years, temperatures have increased across all of Central Asia, which includes parts of China, Uzbekistan and Kyrgyzstan. In the same period, mountain regions have become hotter and wetter — which might have accelerated the retreat of some major glaciers.
Such changes threaten ecosystems and those who rely on them, says Jeffrey Dukes, an ecologist at the Carnegie Institution for Science’s Department of Global Ecology in Stanford, California. The findings are a “great first step” towards informing mitigation and adaptation policies, he says.
The Stockholm conference on the human environment marked the initiation of global consciousness on sustainability. It brought the world together to discuss the big issues of growth and environmental management.
This was the time when Rachel Carson, through her seminal book Silent Spring, had told the story of poisoning of nature. It was also the time when the industrialised West was battling against pollution and toxification.
Our colleague Anil Agarwal, who was at the conference in 1972, often recalled how Stockholm’s lakes were so contaminated with chemicals that you could develop a film negative in the water.
This conference was about the fallout of industrialisation and how to cope and mitigate its harmful impacts.
War destructs and demolishes life, all forms of environment. It’s war’s powerful approach to contradictions within and with environment surrounding life. Wars including the current Ukraine War bear this signature of destruction of and on environment and ecology. The first victim is life; and, then comes surroundings of life that help sustain life. Activities to secure, nourish and sustain environment are hampered/suspended during war, and in war zones also.
Military activities, preparatory to war including training/drills/exercises, itself is threat to environment and ecology. Military/war expenditure is in direct and hostile contradiction with environment and ecology. The expenditure takes away a lot of resources, which can be allocated for life, steps to nourish and secure environment and ecology. The sphere of destruction of environment and ecology widens as the sphere of war widens. Today’s Ukraine is the witness. Iraq and Afghanistan, Yugoslavia and Vietnam are witnesses. Hiroshima and Nagasaki stand as witnesses.
When presenting my research on global institutions established to guide policymaking on environmental challenges, my (mostly North American and European) audiences will often wonder at the need to scrutinise these science-policy interfaces. Isn’t the only thing that matters, someone will inevitably ask, is that we have asked the best scientists on the planet to guide us?
This is typically when I draw from Anil Agarwal and Sunita Narain’s seminal 1991 piece, ‘Global warming in an unequal world’. Agarwal and Narain called out the environmental colonialism evident in a 1990 report by the US-based World Resources Institute purporting to measure a country’s greenhouse gas emissions.
I invite my interlocutors to consider the distinction Agarwal and Narain draw between “luxury” and “survival” emissions. We then consider what gets erased when we take up the now commonplace unit: the metric tonne of carbon dioxide (CO2) or of CO2 equivalent.
From June 5 to June 16, 1972, countries across the world shed a bit of their sovereignty. The aim was to create a common governance structure for the planet’s environment and natural resources.
The occasion was the United Nations Conference on the Human Environment in Stockholm, the first such worldwide convergence on planetary environment, with the theme ‘Only One Earth’.
When the participating 122 countries — 70 of them developing and poor countries — adopted the Stockholm Declaration on June 16, they essentially committed to 26 principles and an action plan that set in a multilateral environmental regime.
One of the overarching principles was that sovereignty should be subject to not causing harm to the environment of other countries as well.
Something that has not changed over 160 years of oil production is the deliberate burning of gas associated with it, called gas flaring. It is turning out to be a major source of methane emission, a greenhouse gas (GHG) “over 80 times more powerful than carbon dioxide as a warming gas on a 20-year timeframe”.
The World Bank’s latest 2022 Global Gas Flaring Tracker Report underscored that the efforts to curb this global warming causing activity have “stalled” in the last one decade.