Global warming, United States politics, Bernie Sanders


This 25 June 2020 CNBC TV video from the USA says about itself:

Here’s how strong hurricane Tropical Storm Laura could become

While Tropical Storm Marco has collapsed, Tropical Storm Laura is expected to rapidly strengthen as it makes its way inland. Louisiana and Texas are now under hurricane watch.

From Senator Bernie Sanders in the USA, 25 August 2020:

Sometimes, when you hear a speech, what is NOT said is more important than what is said.

You wouldn’t know it if you watched the first night of the Republican National Convention, but we are in the middle of a climate emergency with scientists telling us we have just a few years to act in order to save our planet for future generations.

Just look around our country:

The second and third largest fires in the history of the state of California have burned more than 1.2 million acres in just a month, thousands of homes and businesses have been lost to the blaze, and tens of thousands of people have been forced to flee.

But that is not at all.

In the Gulf Coast, a pair of hurricanes threaten to strike within miles of each other and within a 48-hour period this week, a meteorological event unlike any in modern history.

But that too, is not all.

Earlier this month in the Midwest, an 800-mile wide derecho with winds the equivalent of a Category 4 hurricane swept through Iowa and Illinois, causing absolutely catastrophic damage. Homes and businesses were lost. Some estimates say 35 percent of Iowa’s corn was destroyed along with “100 million bushels worth of grain storage and processing infrastructure as well,” according to Iowa’s Secretary of Agriculture.

There’s more:

  • July 2020 was the second-hottest month ever recorded on Earth.
  • June 2020 was the second-hottest June of all time.
  • May 2020 was the hottest May of all time.
  • April 2020 was the second-hottest April of all time.
  • March 2020 was the second-hottest March of all time.
  • February 2020 was the second-hottest February of all time.
  • January 2020 was the hottest January of all time.

But was any of this discussed during last night’s Republican National Convention?

Of course, it wasn’t.

There wasn’t a word about climate change, other than to play a video calling me and our ideas “RADICAL.”

But don’t tell me the Green New Deal is radical.

What is radical is doing nothing to take on the existential threat of climate change while the world burns.

What is radical is the Trump administration opening up the Arctic National Wildlife Refuge to drilling at a time when the Arctic is on fire and we face a serious climate emergency in this country and around the world.

What is radical is doing nothing while scientists tell us very clearly that if we do not act boldly within the next few years in transforming our energy systems away from fossil fuel and into energy efficiency and sustainable energy, the planet we leave our kids and future generations will be increasingly unhealthy and uninhabitable.

What is radical is making the decision to accept more drought, more famine, more floods, more ocean acidification, more extreme weather disturbances, more disease and more human suffering simply to line the pockets of a few greedy fossil fuel executives.

Here is the truth: in the midst of everything going on right now, a global pandemic, an economic meltdown, a struggle for racial justice and more, we simply cannot lose sight of the existential threat of climate change which puts at risk the very survival of this planet.

We cannot go far enough or be too aggressive on this issue.

We are living in absolutely unprecedented times that require us to bring forward an unprecedented response.

I wish I could say we could address our climate crisis with a few tweaks at the edges. But I cannot say that. Now more than ever, we need a Green New Deal to effectively address the existential threat of climate change. So, in my view there are two things we need to do:

Step 1: We must defeat Donald Trump. There is simply no way around just how important it is that we beat him this November and beat him badly.

Step 2: At the same time, we must elect as many progressive candidates as we possibly can who will fight to pass a Green New Deal.

Now, I cannot do that alone. And over the course of the next few months, our supporters are going to be doing everything possible to generate the largest voter turnout in American history, reaching out to people who might otherwise not be voting. We’re going to be doing virtual rallies and town halls in every battleground state. We’ll be making phone calls, sending text messages, and safely distributing literature throughout communities across this country.

That takes resources, but it is important work that must be done. So today, I am asking:

Can you make a $2.70 contribution to help me elect progressives all across this country who will come into office prepared to treat climate change as the existential threat we know it to be? This is important.

We are custodians of the earth. All of us. And it would be a moral disgrace if we left to future generations a planet and that was unhealthy, unsafe, and uninhabitable.

So thank you for making your voice heard.

In solidarity,

Bernie Sanders

Pygmy owls threatened by climate change


This April 2018 video says about itself:

In an old forest in France, we meet a pygmy owl family and discover the feeding and young owls just going out of the niche.

I was privileged to see a pygmy owl near Turku in Finland.

From the University of Turku in Finland:

Climate change may melt the ‘freezers’ of pygmy owls and reduce their overwinter survival

August 5, 2020

Ecologists at the University of Turku, Finland, have discovered that the food hoards pygmy owls collect in nest-boxes (“freezers”) for winter rot due to high precipitation caused by heavy autumn rains and if the hoarding has been initiated early in the autumn. The results of the study show that climate change may impair predators’ foraging and thus decrease local overwinter survival. The study has been published in the internationally esteemed Global Change Biology journal.

Doctoral Candidate Giulia Masoero together with co-authors from the Department of Biology at the University of Turku analysed the unique long-term data set collected by Professor Erkki Korpimäki and his research group in 2003-2018. The aim was to study how the changing weather conditions in late autumn and winter affect the initiation of pygmy owls’ food hoarding as well as the accumulation, use and preservability of the hoarded food. The data set was collected from the Kauhava region in South Bothnia with over 500 food hoards and a research area covering 1,000 square kilometres.

Pygmy owls are small predators that feed on small mammals, especially voles which are their main prey, and birds. Pygmy owls start hoarding for winter usually in late October when the temperature drops below 0° C. They hoard a large amount of prey in tree cavities or nest boxes.

The food stores may be located in multiple nest boxes some kilometres apart. Female owls that are larger than males as well as young owls accumulate larger food stores than males and adult owls.

According to Erkki Korpimäki, the hoarded food is important for pygmy owls during winter, when small mammal prey are under snow and birds are scarce.

“This hoarding behaviour is highly susceptible to global warming because the weather during autumn and winter can affect the condition and usability of the food stores. In several northern areas, autumns have already become warmer and winters milder and rainy. Predictions show that climate change will likely continue along this path and the length of winter will strongly decrease.”

According to the study, the more rainy days there are between mid-October and mid-December, the more likely the food hoards of pygmy owls are to rotten. The owls use rotten food hoards particularly during poor vole years. However, the study showed that having rotten food hoards reduced the recapture probability of female owls in the study area, meaning female owls either die or are forced to leave the area.

“This result indicates that either the use of the rotten low-quality food and/or the energy waste linked with collecting a large food store that will not be used can lead to lower survival or dispersal from the study area,” notes Doctoral Candidate Giulia Masoero.

Pygmy owls might be partly able to adapt to climate change by delaying food hoarding but will more likely suffer due to the changes caused by the warming climate. The results of the study together with global climate predictions thus suggest that climate change has the potential to strongly impair the foraging behaviour and food intake of wintering predators, likely having negative impacts on the boreal forest food web as a whole.

‘Nuclear weapons worsen global warming problem’


This 24 July 2019 video from Britain says about itself:

Interview with Susi Snyder, from the Don’t Bank on the Bomb campaign

Susi Snyder is the project lead for the PAX No Nukes project, she also coordinates the Don’t Bank on the Bomb research and campaign.

From daily The Morning Star in Britain, 3 August 2020:

Nuclear weapons are incompatible with action on climate,’ report warns

CAMPAIGNERS called for a “vigorous and united” movement to abolish nuclear weapons today, as a new report warned of the bomb’s role in climate catastrophe.

Ahead of the 75th anniversary of the Hiroshima and Nagasaki nuclear attacks later this week, Don’t Bank on the Bomb’s study argues that ridding Britain of its nuclear stockpile is essential in addressing climate change.

Nuclear Weapons, the Climate and Our Environment warns that the combination of a new arms race and increasing disruption from climate change make nuclear war more likely.

Big Oil gets billions of taxpayers’ money


This 2017 video from the USA says about itself:

The Cost of Fossil Fuel Subsidies

Understanding how subsidies affect fossil fuel production is crucial to tackling climate change.

This video looks at the latest research into the impact subsidies and support have on the fossil fuel industry, the effect on oil prices and how things may change going forward.

The latest data on US fossil fuel subsidies along with the cost of subsidies and the impact of fossil fuel subsidies are examined and reported. Whilst much discussion on the impact of fossil fuel support and subsidies recently has been on the coal market, the oil and gas subsidies are equally as important. Total US fossil fuel subsidies matter as they are crucially important for climate change. The most recent numbers for fossil fuel subsidies 2016 show that over $300bn is spent annually.

Translated from Daphné Dupont-Nivet and Belia Heilbron in Dutch weekly De Groene, 1 July 2020:

European Union countries support the fossil fuel sector with 137 billion a year …

Henk Kamp is sure: “Fossil fuels are not subsidized in the Netherlands, not even through fiscal measures,” the then Minister of Economic Affairs told the House of Representatives five years ago. The reason was a report by the International Monetary Fund (IMF) that showed that worldwide $ 5300 billion is involved in fossil subsidies. Not from the Netherlands, he thought. His successor Eric Wiebes said it just as clearly in the summer of 2017: “There is no policy to support the fossil sector in particular.” …

The Netherlands has a hodgepodge of tax measures that favour the fossil fuel sector.

For example, the tax exemption on kerosene in aviation and shipping accounts for about 3.5 billion subsidies per year. In addition, there are tax advantages for energy use in greenhouse horticulture and big consumers such as the fossil fuel industry themselves have to pay less energy tax than households. It is less known that the Dutch government provides insurance with which oil refineries are constructed in Kuwait and Oman. …

While parliament is waiting for the inventory, support for fossil fuels is being expanded. Eg, Wiebes has now prepared a bill to expand and increase the investment deduction for the extraction of gas in the North Sea, from 25 to 40 percent. In this way, the Netherlands must be able to compete again with the United Kingdom and Norway, which previously implemented the increase. …

In addition to its activities in Kuwait, the Netherlands supports the installation of oil platforms for the Mexican state oil company Pemex with nearly two hundred million euros, and more than 250 million guarantees for the construction of a new bulk terminal for oil on the coast of Oman, in a nature reserve with protected animal species including four species of sea turtles and the Arabian humpback whale. …

Of all [Dutch taxpayer subsidized] energy projects, 98 percent of the money went to fossil fuel and only two to renewable. …

That does not fit with the climate goal of “Paris” [climate agreement], the Advisory Council on International Affairs, the independent advisory body for government and parliament on international issues, said in July last year. The Council emphasizes that “subsidies, export credits and tax money are currently used for international trade and investment in fossil fuels” …

However, with 1.5 billion euros a year, the Netherlands provides more aid to the fossil fuel industry through export credit insurance than France, Germany or Russia.

Global warming benefits Greenland wolf spiders


This 2019 video says about itself:

Arctic Wolf Spiders‘ Changing Diet May Help Keep Arctic Cool & Lessen Some Impacts of Global Warming

Ecologist Amanda Koltz has a special interest in climate change and spiders. Koltz said she chose to study Arctic wolf spiders because they’re fierce hunters and abundant, making them one of the most important predators in the tundra. Leaving her biology lab at Washington University in St. Louis, Koltz conducts her field research in Northern Alaska. Koltz and her team discovered that Arctic wolf spiders may buffer some of the effects of global warming by helping to ‘keep it cool’. Wolf spiders may play a role decreasing decomposition rates in a warming climate. As the Arctic warms, research shows wolf spiders may dine differently initiating a cascade of food web interactions that could potentially alleviate some impacts of global warming.

From Aarhus University in Denmark:

Spider baby boom in a warmer Arctic

June 25, 2020

Climate change leads to longer growing seasons in the Arctic. A new study, which has just been published in Proceedings of the Royal Society B, show that predators like wolf spiders respond to the changing conditions and have been able to produce two clutches of offspring during the short Arctic summer.

Arctic spiders are at the top of the food chain among invertebrates and are numerous on the Arctic tundra. They typically take several years to become adults, and only produce offspring [once].

But something is happening in the high north in these years. A lot, actually.

Climate change is more dramatic here than in no other place on Earth. The average temperature is increasing significantly and this affects the ecosystems.

Researchers have previously reported how plants bloom earlier and earlier in the season. There are also signs that species move farther north and up into the mountains.

A team of researchers led by senior researcher Toke T. Høye from the Arctic Research Centre and Department of Bioscience at Aarhus University has now shown that changes are also occurring in the reproduction of invertebrates.

For almost 20 years, researchers at the Zackenberg Research Station in north-eastern Greenland have caught wolf spiders as part of the monitoring programme Greenland Ecosystem Monitoring. The spiders were caught in small pitfall traps set up in different vegetation types.

Wolf spiders carry their eggs in a so-called egg sac. The researchers counted the number of eggs in the individual spiders’ egg sacs and compared this information with the time of the season that the animal was caught. By looking at the distribution of the number of eggs in the egg sacs throughout the season, it became clear that in some summers the spiders produced two egg sacs — a phenomenon that is known from warmer latitudes, but which has not previously been observed in the Arctic.

Arctic ecosystems are changing

“We now have the longest time series of spiders collected the Arctic. The large amount of data allows us to show how small animals in the Arctic change their life history in response to climate change,” says Toke T. Høye.

The long time series tells the researchers that the earlier the snow disappears from the ground, the greater the proportion of spiders that can produce a second clutch of offspring.

“These changes in the life history have not been seen earlier and evidence suggests that the phenomenon plays an important role for Arctic insects and spiders,” Toke T. Høye says.

The researchers see the spiders’ response to climate change as an ability to adapt to the new conditions.

Wolf spiders feed on small organisms such as springtails in the soil. If there are more spiders — or insects — in the future Arctic, it can have an influence on the food chains on land.

“We can only speculate about how the ecosystems change, but we can now ascertain that changes in the reproduction of species are an important factor to include when we try to understand how Arctic ecosystems react to the rising temperatures on the planet,” Toke T. Høye says.

Devonian-Carboniferous mass extinction and global warming


This 2015 video says about itself:

New Carboniferous Life

After the Devonian extinction, new types of tetrapods, fish, plants, and other organisms repopulated the world, some of which led to more modern fauna and flora.

From the University of Southampton in England:

Erosion of ozone layer responsible for mass extinction event

May 27, 2020

Researchers at the University of Southampton have shown that an extinction event 360 million years ago, that killed much of the Earth’s plant and freshwater aquatic life, was caused by a brief breakdown of the ozone layer that shields the Earth from damaging ultraviolet (UV) radiation. This is a newly discovered extinction mechanism with profound implications for our warming world today.

There have been a number of mass extinction in the geological past. Only one was caused by an asteroid hitting the Earth, which was 66 million years ago when the dinosaurs became extinct. Three of the others, including the end Permian Great Dying, 252 million years ago, were caused by huge continental-scale volcanic eruptions that destabilised the Earth’s atmospheres and oceans.

Now, scientists have found evidence showing it was high levels of UV radiation which collapsed forest ecosystems and killed off many species of fish and tetrapods (our four-limbed ancestors) at the end of the Devonian geological period, 359 million years ago. This damaging burst of UV radiation occurred as part of one of the Earth’s climate cycles, rather than being caused by a huge volcanic eruption.

The ozone collapse occurred as the climate rapidly warmed following an intense ice age and the researchers suggest that the Earth today could reach comparable temperatures, possibly triggering a similar event. Their findings are published in the journal Science Advances.

The team collected rock samples during expeditions to mountainous polar-regions in East Greenland, which once formed a huge ancient lake bed in the arid interior of the Old Red Sandstone Continent, made up of Europe and North America. This lake was situated in the Earth’s southern hemisphere and would have been similar in nature to modern-day Lake Chad on the edge of the Sahara Desert.

Other rocks were collected from the Andean Mountains above Lake Titicaca in Bolivia. These South American samples were from the southern continent of Gondwana, which was closer to the Devonian South Pole. They held clues as to what was happening at the edge of the melting Devonian ice sheet, allowing a comparison between the extinction event close to the pole and close to the equator.

Back in the lab, the rocks were dissolved in hydrofluoric acid, releasing microscopic plant spores (like pollen, but from fern-like plants that didn’t have seeds or flowers) which had lain preserved for hundreds of millions of years. On microscopic examination, the scientists found many of the spores had bizarrely formed spines on their surface — a response to UV radiation damaging their DNA. Also, many spores had dark pigmented walls, thought to be a kind of protective ‘tan’, due to increased and damaging UV levels.

The scientists concluded that, during a time of rapid global warming, the ozone layer collapsed for a short period, exposing life on Earth to harmful levels of UV radiation and triggering a mass extinction event on land and in shallow water at the Devonian-Carboniferous boundary.

Following melting of the ice sheets, the climate was very warm, with the increased heat above continents pushing more naturally generated ozone-destroying chemicals into the upper atmosphere. This let in high levels of UV-B radiation for several thousand years.

Lead researcher Professor John Marshall, of the University of Southampton’s School of Ocean and Earth Science, who is a National Geographic Explorer, comments: “Our ozone shield vanished for a short time in this ancient period, coinciding with a brief and quick warming of the Earth. Our ozone layer is naturally in a state of flux — constantly being created and lost — and we have shown this happened in the past too, without a catalyst such as a continental scale volcanic eruption.”

During the extinction, plants selectively survived, but were enormously disrupted as the forest ecosystem collapsed. The dominant group of armoured fish became extinct. Those that survived — sharks and bony fish — remain to this day the dominant fish in our ecosystems.

These extinctions came at a key time for the evolution of our own ancestors, the tetrapods. These early tetrapods are fish that evolved to have limbs rather than fins, but still mostly lived in water. Their limbs possessed many fingers and toes. The extinction reset the direction of their evolution with the post-extinction survivors being terrestrial and with the number of fingers and toes reduced to five.

Professor Marshall says his team’s findings have startling implications for life on Earth today: “Current estimates suggest we will reach similar global temperatures to those of 360 million years ago, with the possibility that a similar collapse of the ozone layer could occur again, exposing surface and shallow sea life to deadly radiation. This would move us from the current state of climate change, to a climate emergency.”

The remote locations visited in East Greenland are very difficult to access, with travel involving light aircraft capable of landing directly on the tundra. Transport within the vast field area was by inflatable boats equipped with outboard motors, all of which had to fit in the small aircraft.

All field logistics was organised by CASP, an independent charitable trust based in Cambridge specialising in remote geological fieldwork. Mike Curtis, Managing Director of CASP says: “We have a history of assisting research geologists such as John Marshall and colleagues to access remote field areas and we are particularly pleased that their research has proved to have such potentially profound implications.”

Forest wildlife worldwide, video


This 17 April 2020 video says about itself:

Our Planet | Forests

Experience our planet’s natural beauty and examine how climate change impacts all living creatures in this ambitious documentary of spectacular scope.

In this episode: Examine the fragile interdependence that exists between forests’ wide variety of residents, including bald eagles, hunting dogs and Siberian tigers.

Antarctic penguins and climate change


This 8 April 2020 video says about itself:

Antarctica, climate change and a tale of two penguins

Jonathan Watts visits Antarctica with a team of scientists to look at how human activity and rising temperatures are creating winners and losers among penguins – and why this should be a warning to us all.

Food wrapping, fishing gear and plastic waste continue to reach the Antarctic. Two new studies detail how plastic debris is reaching sub-Antarctic islands: here.

American robin migration and climate change


This 2019 video from the USA is called 5 Lovable Things About American Robins.

From the Earth Institute at Columbia University in the USA:

American robins now migrate 12 days earlier than in 1994

New GPS data show birds adjust to shifting snow conditions as climate warms

April 1, 2020

Summary: A new study concludes that robin migration is kicking off earlier by about five days each decade. The study is also the first to reveal the environmental conditions along the migration route that help the birds keep up with the changing seasons.

Every spring, American robins migrate north from all over the U.S. and Mexico, flying up to 250 miles a day to reach their breeding grounds in Canada and Alaska. There, they spend the short summer in a mad rush to find a mate, build a nest, raise a family, and fatten up before the long haul back south.

Now climate change is making seasonal rhythms less predictable, and springtime is arriving earlier in many parts of the Arctic. Are robins changing the timing of their migration to keep pace, and if so, how do they know when to migrate? Although many animals are adjusting the timing of their migration, the factors driving these changes in migratory behavior have remained poorly understood.

A new study, published in Environmental Research Letters, concludes that robin migration is kicking off earlier by about five days each decade. The study is also the first to reveal the environmental conditions along the migration route that help the birds keep up with the changing seasons. Lead author Ruth Oliver completed the work while earning her doctorate at Columbia University’s Lamont-Doherty Earth Observatory.

At Canada’s Slave Lake, a pit stop for migrating birds, researchers have been recording spring migration timing for a quarter-century. Their visual surveys and netting censuses revealed that robins have been migrating about five days earlier per decade since 1994.

In order to understand what factors are driving the earlier migration, Oliver and Lamont associate research professor Natalie Boelman, a coauthor on the paper, knew they needed to take a look at the flight paths of individual robins.

Their solution was to attach tiny GPS “backpacks” to the birds, after netting them at Slave Lake in mid-migration. “We made these little harnesses out of nylon string,” Oliver explained. “It basically goes around their neck, down their chest and through their legs, then back around to the backpack.” The unit weighs less than a nickel — light enough for the robins to fly unhindered. The researchers expect that the thin nylon string eventually degrades, allowing the backpacks to fall off.

The researchers slipped these backpacks onto a total of 55 robins, tracking their movements for the months of April through June. With the precise location from the GPS, the team was able to link the birds’ movements with weather data on air temperature, snow depth, wind speed, precipitation, and other conditions that might help or hinder migration.

The results showed that the robins start heading north earlier when winters are warm and dry, and suggest that local environmental conditions along the way help to fine-tune their flight schedules.

“The one factor that seemed the most consistent was snow conditions and when things melt. That’s very new,” said Oliver. “We’ve generally felt like birds must be responding to when food is available — when snow melts and there are insects to get at — but we’ve never had data like this before.”

Boelman added that “with this sort of quantitative understanding of what matters to the birds as they are migrating, we can develop predictive models” that forecast the birds’ responses as the climate continues to warm. “Because the timing of migration can indirectly influence the reproductive success of an individual, understanding controls over the timing of migratory events is important.”

For now, it seems as though the environmental cues are helping the robins to keep pace with the shifting seasons. “The missing piece is, to what extent are they already pushing their behavioral flexibility, or how much more do they have to go?” said Oliver.

Because the study caught the birds in mid-migration, the tracking data doesn’t reflect the birds’ full migration path. To overcome this limitation, the researchers plan to analyze tissue from the robins’ feathers and claws, which they collected while attaching the GPS harnesses, to estimate where each bird spent the previous winter and summer.

Over the long term, Oliver says, she hopes to use the GPS trackers to sort out other mysteries as well, such as how much of the change in migration timing is due to the behavioral responses found in the study versus natural selection to changing environments, or other factors.

“This type of work will be really cool once we can track individuals throughout the course of their life, and that’s on the near-term horizon, in terms of technological capabilities,” she said. “I think that will really help us unpack some of the intricacies of these questions.”

The new study is part of a broader NASA-funded research and outreach project, called the Arctic-Boreal Vulnerability Experiment, that is tracking how the rapid warming of the far north affects wildlife. Read more about the project on the researchers’ blog: https://earthobservatory.nasa.gov/blogs/fromthefield/2016/04/12/a-migration-mystery/

Oliver is now a postdoctoral associate at Yale University. Other authors on the study include Peter Mahoney from the University of Washington, Eliezer Gurarie from the University of Washington and the University of Maryland, Nicole Krikun from the Lesser Slave Lake Bird Observatory, Brian Weeks from the University of Michigan, Mark Hebblewhite from the University of Montana, and Glen Liston from Colorado State University.

With the western United States and northern Mexico suffering an ever-lengthening string of dry years starting in 2000, scientists have been warning for some time that climate change may be pushing the region toward an extreme long-term drought worse than any in recorded history. A new study says the time has arrived: a megadrought as bad or worse than anything even from known prehistory is very likely in progress, and warming climate is playing a key role. The study, based on modern weather observations, 1,200 years of tree-ring data and dozens of climate models, appears this week in the leading journal Science: here.

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.”