Melting glaciers could create new habitats for Pacific salmon

Nature Communications

US Fish & Wildlife Service`

Melting glaciers in western North America could create new habitats for Pacific salmon over the next century, a modelling study in Nature Communications suggests. 

Migratory Pacific salmon are one group of species whose abundances have dramatically shifted in response to changing climate patterns, however, the warming of Arctic and subarctic streams, in combination with glacier retreat, could create potential new habitats for salmon. Previous work has observed the colonization of newly de-glaciated streams by salmon, but predicting future shifts in salmon habitat across regions has been difficult. 

Kara Pitman and colleagues modelled glacier retreat under different climate change scenarios for a 623,000 km2 region of western North America. They quantified emerging streams created by glacier retreat, which they combined with stream gradient-based salmon habitat models. 

By 2100, the authors project that approximately 6,000 km of new streams will be accessible to Pacific salmon and, of this newly accessible habitat, nearly 2,000 km will be suitable for spawning and juvenile rearing. 

The authors note that glacier retreat is only one consequence of climate change and other climate-induced effects such as ocean heat waves, sea-level rise and extreme flood events could all cause widespread declines in salmon abundance. 

Glacier retreat also creates new prospects for industries such as mining, which can degrade salmon habitat. Understanding the timing and location of emerging salmon habitat is critical to informing conservation planning and to avoid degradation of future salmon habitat, the authors conclude.

Major toilet paper brands are flushing our forests down the drain

The National Observer

What runs through your mind when you’re deciding which toilet paper to buy? Sale price, roll size, pitiful single-ply or luxurious triple? Climate change might not make your list of considerations, but it should. Story here.

Please also watch this video.

"Truth in Advertising - a TV commercial as it should be"

Nearly Half the World's Children at 'Extremely High Risk' for Facing Effects of Climate Crisis, Report Finds

Common Dreams

 OCHA/Giles Clarke. Displaced children stand in the shredded remains of tents in Abs settlement, Yemen, for internally displaced persons. Located just 40 km from the frontlines, the settlement is regularly damaged by passing sandstorms.

"Virtually no child's life will be unaffected" by the climate emergency, said the director of UNICEF. Story here.

‘Negligible’ long-term impacts on climate from COVID-19 restrictions

Nature Climate Change

Empty streets during the Covid shutdown in Zaragoza City, Spain, Mar. 2020.
A Wikimedia photo.

The decline in greenhouse-gas emissions and air pollutants, as a result of policies to prevent the spread of COVID-19, will have a negligible impact on long-term warming and may lead to cooling of just 0.005–0.01 °C by 2030, suggests a paper in Nature Climate Change. However, the findings also suggest that if a ‘green recovery’ is pursued, warming could possibly be kept within the 1.5 °C limit above pre-industrial levels by 2050.

The enforcement of policies to limit the spread of COVID-19 has had a significant impact on travel and work. This lack of mobility has led to substantial declines in greenhouse-gas emissions and air pollutants. Previous research has examined the immediate impacts of COVID-19 policies on emissions; however, the long-term impacts of these policies are not well understood.

Piers Forster and colleagues analysed mobility data from 123 countries to estimate emission changes due to the COVID-19 restrictions from February to June 2020. Their analysis suggests that the reductions in emissions are likely to have peaked in April 2020. The authors suggest that nitrogen oxides (NOx) declined by 30% in April, which contributed to short-term cooling. However, this was offset by a 20% decline in sulfur dioxide (SO2), which weakened the aerosol cooling affect and contributed to short-term warming. They use these estimates to project future changes and compare them to a baseline scenario of current national policies. They found that these short-term effects end by 2025, leaving a longer term slight cooling of 0.01 °C from reduced atmospheric concentrations of carbon dioxide compared to concentrations under baseline policies.

To assess the longer-term impacts, the authors modelled four recovery scenarios, including a fossil fuel-based recovery and green stimulus packages. They suggest that the different scenarios have a minimal impact on the 2020–2030 climate response, but that differences emerge after 2030. They find that the two-year ‘blip pathway’, where the economic recovery maintains current investment levels, and a recovery with fossil fuel stimulus are likely to result in warming of over 1.5 °C [NOT: 2 °C] by 2050. Conversely, choosing a strong green recovery that includes low-carbon energy supply as well as energy efficiency and does not support bailouts for fossil firms could limit warming by 0.3 °C and keep warming within 1.5 °C above pre-industrial levels.

The authors highlight that economic recovery choices will affect the warming trajectory by the mid-century and argue that a green recovery is important for ensuring the goals of the Paris Agreement are met.