Climate change threatens nightingale migration


This 2010 video from England is called Nightingale (Luscinia megarhynchos).

From the American Ornithological Society Publications Office:

Climate change may be making migration harder by shortening nightingales’ wings

April 1, 2020

The Common Nightingale, known for its beautiful song, breeds in Europe and parts of Asia and migrates to sub-Saharan Africa every winter. A new study published in The Auk: Ornithological Advances suggests that natural selection driven by climate change is causing these iconic birds to evolve shorter wings, which might make them less likely to survive their annual migration.

Complutense University of Madrid’s Carolina Remacha and Javier Pérez-Tris and their colleagues analyzed twenty years of data on wing shape variation and survival in two populations of nightingales from central Spain. They found that nightingales’ average wing length relative to their body size has decreased over the past two decades, becoming less optimal for migration. Shorter-winged birds were less likely to return to their breeding grounds after their first round-trip to Africa. But if this change in wing length is negatively affecting survival, what is driving it?

The “migratory gene package” hypothesis predicts that a suite of adaptations related to migration — including a long wingspan as well as a higher resting metabolic rate, larger clutch size, and shorter lifespan — may all be controlled by a set of genes that are linked so that selective pressures on one trait also affect the others. In recent decades, the timing of spring has shifted in central Spain and summer droughts have become longer and more intense, leaving nightingales with a shorter window in which to raise their young. This means the most successful birds may be those that lay smaller clutches of eggs, giving them fewer young to care for. And if natural selection is favoring smaller clutches, it may simultaneously push nightingales away from all of the linked traits in the “migratory gene package.”

Natural selection on clutch size that inadvertently leads to shorter wings and, therefore, reduced survival is an example of “maladaptation”, where organisms’ responses to changing conditions end up being harmful instead of helpful. “There is much evidence that climate change is having an effect on migratory birds, changing their arrival and laying dates and their physical features over the last few decades,” says lead author Carolina Remacha. “If we are to fully understand how bird populations adapt to new environments in order to help them tackle the challenges of a rapidly changing world, it is important to call attention to the potential problems of maladaptive change.”

Greta Thunberg on coronavirus and climate crisis


This 30 March 2020 New Scientist video says about itself:

Greta Thunberg: We must fight the climate crisis and pandemic simultaneously

The world needs to tackle the coronavirus pandemic and climate change simultaneously, and guard against people who try to use the current crisis to delay action cutting carbon emissions, Greta Thunberg explains in this conversation with New Scientist‘s chief reporter, Adam Vaughan.

The Swedish climate activist, who revealed last week that she and her father had likely had Covid-19, said the response to the virus outbreak revealed societal shortcomings, as well as our abilities to change in the face of a crisis, but had proved they can act fast.

“If one virus can wipe out the entire economy in a matter of weeks and shut down societies then that is a proof that our societies are not very resilient. It also shows that once we are in an emergency, we can act and we can change our behaviour quickly”, she says.

Australian wildfires, climate change wildfires


This 15 January 2020 video says about itself:

Australia fires: Climate change increases the risk of wildfires – BBC News

UK scientists say the recent fires in Australia are a taste of what the world will experience as temperatures rise.

Prof Richard Betts from the Met Office Hadley Centre said we are “seeing a sign of what would be normal conditions under a future warming world of 3C”.

While natural weather patterns have driven recent fires, researchers said it’s “common sense” that human-induced heating is playing a role.

Last year was Australia’s warmest and driest year on record.

UK researchers have carried out a rapid analysis of the impact of climate change on the risk of wildfires happening all over the world. Their study looked at 57 research papers published since the last major review of climate science came out in 2013.

By Carolyn Gramling, March 4, 2020 at 12:39 pm:

Australia’s wildfires have now been linked to climate change

Climate-influenced temperatures raised the wildfire risk by 30 percent

Human-caused climate change made southeastern Australia’s devastating wildfires during 2019–2020 at least 30 percent more likely to occur, researchers report in a new study published online March 4.

A prolonged heatwave that baked the country in 2019-2020 was the primary factor raising the fire risk, said climate scientist Geert Jan van Oldenborgh, with the Royal Netherlands Meteorological Institute in De Bilt. The study also linked the extremity of that heatwave to climate change, van Oldenborgh said March 3 during a news conference to explain the findings. Such an intense heatwave in the region is about 10 times more likely now than it was in 1900, the study found.

Van Oldenborgh also noted that climate simulations tend to underestimate the severity of such heatwaves, suggesting that climate change may be responsible for even more of the region’s high fire risk. “We put the lower boundary at 30 percent, but it could well be much, much more,” he said.

This week, the southeastern Australia region was declared free of wildfires for the first time in over 240 days, according to a statement March 2 by the New South Wales Rural Fire Service on Twitter. The fires have burned through an estimated 11 million hectares, killing at least 34 people and destroying about 6,000 buildings since early July. About 1.5 billion animals also died in the blazes. Researchers are still tallying the damage and assessing the potential for recovery for many native plant and animal species (SN: 2/11/20).

The climate attribution study was conducted by the World Weather Attribution group, an international consortium of researchers who investigate how much of a role climate change might be playing in natural disasters. Given the quick turnaround time, the study has not yet been peer-reviewed. “We wanted to bring the scientific evidence [forward] at a time when the public is talking about the event,” said climate modeler Friederike Otto of the University of Oxford. Then the group examined how climate change altered the Fire Weather Index, an estimation of the risk of wildfires.

The climate simulations show that the probability of a high Fire Weather Index during the 2019–2020 season increased by at least 30 percent, relative to the fire risk in 1910. That is primarily due to the increase in extreme heat; the study was not able to determine the impact of climate change on extreme drought conditions, which also helped fuel the blazes.

Researchers previously have suggested that an El Niño-like atmosphere-ocean weather pattern known as the Indian Ocean Dipole, which was in a strong positive phase in 2019, may have played a role in exacerbating the dry conditions (SN: 1/9/20). Global warming may make such extreme positive phases of this pattern more common. The new study confirmed that the 2019 positive phase made drought conditions more extreme, but could not confirm this particular phase’s relationship to climate change.

“It is always rather difficult to attribute an individual event to climate change,” but this study is nicely done, says Wenju Cai, a climate scientist at CSIRO who is based in Melbourne, Australia. The link identified to climate change is reasonable, if not particularly surprising, he says.

The year 2019 was Australia’s hottest and driest since modern recordkeeping began in the country in 1910. Summers Down Under also appear to be lengthening: The Australia Institute, a Canberra-based think tank, released a report March 2 that found that Australian summers during the years 1999 to 2018 lasted longer by a month, on average, than they did 50 years ago.

Temperature observations going back to 1910 show that the region’s temperatures have risen by about 2 degrees Celsius on average, van Oldenborgh and colleagues report. The climate simulations underrepresented that warming, however, showing an increase of only 1 degree Celsius in that time.

Climate modelers previously have struggled to reconcile the disparity between recorded temperatures and simulated heatwaves: Simulations tend to underestimate the severity of the extreme events. The team noticed a similar underestimation in its simulations of the 2019 heat waves in Europe (SN: 7/2/19). Conditions not generally factored into regional climate simulations, such as land-use changes, may be responsible for the disparity. Changes in vegetation cover, for example, can have an impact on how hot or dry a region gets.

New international research has found a worrying change in the Indian Ocean’s surface temperatures that puts southeast Australia on course for increasingly hot and dry conditions: here.

How scientists wrestle with grief over climate change. Those who study nature are dealing with frustration and sadness over what’s being lost: here.

Florida, USA turtles threatened by climate change


This 27 February 2013 video from the USA says about itself:

Park rangers release rehabilitated juvenile loggerhead turtles at Cape Canaveral Seashore immediately adjacent to NASA‘s Kennedy Space Center. I got to help since I happened upon the event during a beach stroll.

From the University of Central Florida in the USA:

Sea level rise impacts to Canaveral sea turtle nests will be substantial

March 4, 2020

Sea level rise and hurricanes are a threat to sea turtle nesting habitat along national seashores in the Southeast, but a new study predicts the greatest impact to turtles will be at Canaveral National Seashore.

The University of Central Florida-led study, which was published recently in the journal Ecological Applications, examined loggerhead and green sea turtle nests to predict the amount of beach habitat loss at Canaveral, Cumberland Island, Cape Lookout, and Cape Hatteras national seashores by the year 2100. Sea turtles help maintain the coastal ecosystem and are indicators for the health of sandy beaches.

When comparing sea turtle nesting density with predicted beach loss at the sites, they found nesting habitat loss would not be equal. The researchers predicted that by 2100, Canaveral would lose about 1 percent of its loggerhead habitat, while the three other seashores will lose between approximately 2.5 to 6.7 percent each.

Although Canaveral’s percentage loss is smaller, the impact at this national seashore will be greater because of its nesting density.

“Canaveral is part of the core loggerhead nesting area for the Southeast,” says Marta Lyons, a preeminent postdoctoral fellow in UCF’s Department of Biology and the study’s lead author. “The nests are already pretty well packed in there, so even a small loss of area can have a big impact on nesting sea turtle populations.”

To determine beach loss at the study sites, the researchers used sea level rise and storm surge estimates and considered the effects of impervious structures along the shorelines, such as roads and buildings, in restricting natural beach movement. To do this, they developed a new method to calculate current and future sea turtle nesting areas that takes into account nesting data, beach length and width, and the impact of impervious surfaces.

Lyons says one of the goals was to create digital maps for the National Park Service to understand how sea turtle nesting areas will change with sea level rise and how resources could be managed.

“As the National Park Service thinks about future developments, whether that’s putting in a new lifeguard station or new bathrooms, this method of calculating current and future sea turtle nesting area can help them decide where to put them,” she says.

Sea turtles around the world are threatened by marine plastic debris, mostly through ingestion and entanglement. Now, researchers have new evidence to explain why all that plastic is so dangerous for the turtles: they mistake the scent of stinky plastic for food: here.