The most important issue about water is not supply, but how it is used

Nature Portfolio (Springer Nature) | December 14th, 2023

The Northern California 2018 Extreme Fire Season

American Meteorological Society (AMS) | February 19th, 2020

The fire season of 2018 was the most extreme on record in Northern California in terms of the number of fatalities (95), over 22,000 structures destroyed, and over 600,00

The fire season of 2018 was the most extreme on record in Northern California in terms of the number of fatalities (95), over 22,000 structures destroyed, and over 600,000 ha burned. The most deadly and destructive fire in California history, the Camp Fire, occurred in Butte County in the Sierra Nevada foothills in early November, and caused 85 fatalities and destroyed nearly 19,000 structures. The largest fire complex in state history, the Mendocino Complex, which included the Ranch fire, the largest single fire in state history, burned nearly 186,000 ha. It occurred in July and August, killing one firefighter. In western Shasta County nearly 138,000 ha burned from July through September in the Carr, Hirz, and Delta Fires. These fires caused multiple closures of Interstate 5 and exhibited some of the most extreme fire behavior ever observed in California. The Carr Fire caused eight fatalities, including two firefighters and two workers supporting firefighting efforts, burned over 1,100 homes in west Redding, caused the evacuation of one-third of the city, and produced an extreme fire vortex with an Enhanced Fujita scale rating between 136 to 165 mph, making it arguably the strongest tornado type event in state history, and one of the strongest documented cases in the world (Lareau et al. 2018).

The Ocean and Cryosphere in a Changing Climate

Intergovernmental Panel on Climate Change (IPCC) | September 24th, 2019

All people on Earth depend directly or indirectly on the ocean and cryosphere. The global ocean covers 71% of the Earth surface and contains about 97% of the Earth’s w

All people on Earth depend directly or indirectly on the ocean and cryosphere. The global ocean covers 71% of the Earth surface and contains about 97% of the Earth’s water. The cryosphere refers to frozen components of the Earth system. Around 10% of Earth’s land area is covered by glaciers or ice sheets. The ocean and cryosphere support unique habitats, and are interconnected with other components of the climate system through global exchange of water, energy and carbon. The projected responses of the ocean and cryosphere to past and current human-induced greenhouse gas emissions and ongoing global warming include climate feedbacks, changes over decades to millennia that cannot be avoided, thresholds of abrupt change, and irreversibility. Human communities in close connection with coastal environments, small islands (including Small Island Developing States, SIDS), polar areas and high mountains are particularly exposed to ocean and cryosphere change, such as sea level rise, extreme sea level and shrinking cryosphere. Other communities further from the coast are also exposed to changes in the ocean, such as through extreme weather events. Today, around 4 million people live permanently in the Arctic region, of whom 10% are Indigenous. The low-lying coastal zone8 is currently home to around 680 million people (nearly 10% of the 2010 global population), projected to reach more than one billion by 2050. SIDS are home to 65 million people. Around 670 million people (nearly 10% of the 2010 global population), including Indigenous peoples, live in high mountain regions in all continents except Antarctica. In high mountain regions, population is projected to reach between 740 and 840 million by 2050 (about 8.4–8.7% of the projected global population). In addition to their role within the climate system, such as the uptake and redistribution of natural and anthropogenic carbon dioxide (CO2) and heat, as well as ecosystem support, services provided to people by the ocean and/or cryosphere include food and water supply, renewable energy, and benefits for health and well-being, cultural values, tourism, trade, and transport. The state of the ocean and cryosphere interacts with each aspect of sustainability reflected in the United Nations Sustainable Development Goals (SDGs). Over the last decades, global warming has led to widespread shrinking of the cryosphere, with mass loss from ice sheets and glaciers (very high confidence), reductions in snow cover (high confidence) and Arctic sea ice extent and thickness (very high confidence), and increased permafrost temperature (very high confidence).

The Pacific Decadal Oscillation modulated marine heatwaves in the Northeast Pacific during past decades

Nature Portfolio (Springer Nature) | June 19th, 2023

The past and future of global river ice

Nature Portfolio (Springer Nature) | January 1st, 2020

More than one-third of Earth’s landmass is drained by rivers that seasonally freeze over. Ice transforms the hydrologic, ecologic, climatic and socio-economic  functi

More than one-third of Earth’s landmass is drained by rivers that seasonally freeze over. Ice transforms the hydrologic, ecologic, climatic and socio-economic  functions of river corridors. Although river ice extent has been shown to be declining in many regions of the world, the seasonality, historical change and predicted future changes in river ice extent and duration have not yet been quantified globally. Previous studies of river ice, which suggested that declines in extent and duration could be attributed to warming temperatures, were based on data from sparse locations. Furthermore, existing projections of future ice extent are based solely on the location of the 0-°C isotherm. Here, using satellite observations, we show that the global extent of river ice is declining, and we project a mean decrease in seasonal ice duration of 6.10 ± 0.08 days per 1-°C increase in global mean surface air temperature. We tracked the extent of river ice using over 400,000 clear-sky Landsat images spanning 1984–2018 and observed a mean decline of 2.5 percentage points globally in the past three decades. To project future changes in river ice extent, we developed an observationally calibrated and validated model, based on temperature and season, which reduced the mean bias by 87 per cent compared with the 0-degree-Celsius isotherm approach. We applied this model to future climate projections for 2080–2100: compared with 2009–2029, the average river ice duration declines by 16.7 days under Representative Concentration Pathway (RCP) 8.5, whereas under RCP 4.5 it declines on average by 7.3 days. Our results show that, globally, river ice is measurably declining and will continue to decline linearly with projected increases in surface air temperature towards the end of this century.

The pattern of fresh‐water flow in a coastal aquifer

American Geophysical Union (AGU) | April 1st, 1959

Formulas are developed for the flow pattern followed by the seaward‐moving fresh ground water as it nears a beach. It is found that, under steady flow conditions, a sha

Formulas are developed for the flow pattern followed by the seaward‐moving fresh ground water as it nears a beach. It is found that, under steady flow conditions, a sharply defined interface is formed between the fresh and salt water. Along the interface the pressure of the static salt water, owing to its greater density, is counterbalanced by the pressures which drive the fresh water seaward. The fresh water escapes through a gap between this interface and the shore line. An increase in the flow of fresh water widens the gap. Tidal action causes a diffusion of salt water across the interface. This salt is carried back to sea with the fresh‐water flow.

The potential of collaborative solutions to improve management of California (United States) wildlands

Restoration Ecology, Society for Ecological Restoration (SER) | November 13th, 2024

The potential of urban irrigation for counteracting carbon-climate feedback

Nature Portfolio (Springer Nature) | March 18th, 2024

The Press and Pulse of Climate Change: Extreme Events in the Colorado River Basin

American Water Resources Association (AWRA) | June 21st, 2022

Extremes in temperature and precipitation are associated with damaging floods, prolonged drought, destructive wildfires, agricultural challenges, compromised human health

Extremes in temperature and precipitation are associated with damaging floods, prolonged drought, destructive wildfires, agricultural challenges, compromised human health, vulnerable infrastructure, and threatened ecosystems and species. Often, the steady and progressive trends (or presses) of rising global temperature are the central focus in how climate impacts are described. However, observations of extreme weather events (or pulses) increasingly show that the intensity, duration and/or frequency of acute events are also changing, resulting in greater impacts on communities and the environment. Describing how the influence of extreme events may shape water management in the Colorado River Basin in clear terms is critical to sound future planning and efforts to manage risk. Three scenario planning workshops in 2019 and 2020 were held as part of a Colorado River Conversations series, identifying potential impacts from multiple intersecting extreme events. Water managers identified climate-related events of concern in the Colorado River Basin that necessitate greater attention and adaptive responses. To support efforts to include consideration of climate-change-driven extremes in water management and planning, we explore the current state of knowledge at the confluence of long-term climate shifts and extreme weather in the Colorado River Basin related to the events of concern that were identified by scenario planning participants.

The reduced net carbon uptake over Northern Hemisphere land causes the close-to-normal CO2 growth rate in 2021 La Niña

American Association for the Advancement of Science (AAAS) | June 7th, 2024