Why rain on snow in the California mountains worries scientists

Rain-on-snow events have resulted in some of the nation’s most destructive and costly floods

Keith Musselman

Down To Earth | March 15, 2023

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.

CO2 Levels Are the Highest in a Million Years as Extreme Weather and Flooding Rage Across the Globe

Juan Cole

Countercurrents | September 01, 2022

Girls use a temporary raft across a flooded street in a residential area after heavy monsoon rains in Karachi on July 26, 2022. A weather emergency was declared in Karachi as heavier-than-usual monsoon rains continue to lash Pakistan’s biggest city, flooding homes and making streets impassable. (Photo: Rizwan Tabassum/AFP via Getty Images)

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.

GHG Concentrations, Sea levels And Ocean Heat Hit Record Highs In 2021

Countercurrents | September 01, 2022

The annual State of the Climate report ( https://ametsoc.net/sotc2021/StateoftheClimate2021_lowres.pdf)  report published Wednesday in the U.S. shows that in 2021, greenhouse gas (GHG) levels, global sea levels, and ocean heat reached record highs.

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.”

Climate change is turning more of Central Asia into desert

The rapid expansion will have significant impacts on ecosystems and the people and animals who rely on them.

Giorgia Guglielmi

Nature | June 16, 2022

The spread of deserts in Uzbekistan and neighbouring countries will alter the composition of ecosystems.Credit: Matyas Rehak/Shutterstock

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.

Stockholm syndrome: What should ‘+50’ be about

The 50th anniversary celebration of the Stockholm conference should be about our common future, not the divisions of the past

Sunita Narain

Down To Earth | June 01, 2022

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.

Environment and war today

Farooque Chowdhury

Countercurrents | June 05, 2022

War environs environment.

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.

Stockholm+50: Is science for just solutions

If science-policy interfaces are to deliver just and effective solutions to climate change, they must involve indigenous peoples and local communities

Pia M Kohler

Down To Earth | June 04, 2022

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.

Stockholm+50: We need decentralisation of ‘power’

Power generation and transmission models that are local and self-sustaining can increase access to energy in the future

Koshy Mathew Cherail

Down To Earth | June 03, 2022

Availability and access to uninterrupted and reliable energy sources is a prerequisite to enable an equitable and just development of communities, nations, and regions at large.

Countries that have clear goals of raising the socio-economic conditions of their population have prioritised access to energy above other development goals.

Construction and operation of power plants, as well as ensuring a steady supply of fuel of consistent quality, is a time-consuming and capital-intensive process.

50 years since Stockholm conference: The summer lingers

Richard Mahapatra

Down To Earth | May 31, 2022

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.

Global warming: 400 million tonnes CO2 pumped to atmosphere a year from this source the world is blind to

Gas flared at and gas facilities is greater than EU’s total import from Russia and a key source of methane emission

Down To Earth | May 06, 2022

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.