Scotland to ditch key climate change target

Kevin Keane - BBC Scotland's environment correspondent
Wed, April 17, 2024 

Scotland was aiming to cut emissions by 75% by the end of the decade [PA Media

The Scottish government is to ditch its flagship target of reducing greenhouse gas emissions by 75% by 2030.

The final goal of reaching "net-zero" by 2045 will remain, but BBC Scotland News understands the government's annual climate targets could also go.

Ministers have missed eight of the last 12 annual targets and have been told that reaching the 75% milestone by the end of the decade is unachievable.


A statement is expected at Holyrood on Thursday afternoon.

The Climate Change Committee (CCC) - which provides independent advice to ministers - warned back in 2022 that Scotland had lost its lead over the rest of the UK in tackling the issue.

Last year ministers failed to publish a plan it promised - required under the act - detailing how they were going to meet the targets.

Scottish government climate targets unachievable, says watchdog


Scotland's climate 'changing faster than expected'


Scotland loses climate change lead, advisers warn

Then in March of this year the CCC said for the first time that the 2030 target was unreachable.

Former first minister Nicola Sturgeon saw her SNP administration as world leaders on climate change when the targets were introduced in 2019, often asserting that Scotland had the "most stretching targets in the world."

Hers was the first government in the world to declare a climate emergency and Glasgow hosted the COP26 climate summit in 2021, yet environmentalists believe the emergency response never came.

So scrapping the targets will be seen as an embarrassing retreat for the SNP and the Scottish Greens, their partners in the Scottish government.

Scotland's emissions reduction target for 2030 was tougher than for the UK as a whole, which was for a reduction of 68% by the same date.
Where did the targets come from?

There was a febrile atmosphere around back in 2019 when the Scottish Parliament passed its landmark legislation to speed up the rate of decarbonisation

It was the height of the school climate strikes and just a few days earlier thousands had taken to the streets in support of Greta Thunberg's calls for more action.

Nicola Sturgeon - pictured here with Greta Thunberg and climate activist Vanessa Nakate - portrayed her government as being climate leaders at COP26 in Glasgow

 [PA Media]

At Holyrood, parties were trying to outbid each other on how quickly the country could go, eventually settling on a pace far beyond what experts had planned for.

The Scottish Greens - who are now in government with the SNP - proposed aiming to cut emissions by a whopping 80% compared with the baseline year of 1990.

But parliament settled on 75% - still 5% more than recommended - and the Climate Change Bill was agreed by all parties except the Greens, who abstained.

One former minister told me there was a "lack of realism" at the time.
What went wrong?

The new legislation required ministers to set annual targets for reducing emissions.

In a sense it was a hostage to fortune with the yearly totals heavily influenced by the winter weather which determines how much gas we use to heat up our homes.

But the trend was clear as eight out of 12 of the targets were missed.

Protestors marched to a rally in Holyrood Park in Edinburgh in the days before the climate targets were set [Getty Images]

With the closure of Scotland's last coal-fired power station at Longannet in 2016, politicians conceded that the low-hanging fruit had all been picked and any future progress would require big changes to how we live our lives.

But the Greens believe the current system has fundamentally failed with too much emphasis placed on targets rather than policies.

That might be how the Greens try to convince their voters that scrapping the targets will be the right decision.

Scottish Greens climate spokesman Mark Ruskell said the party was "absolutely determined to accelerate the urgent and substantial action needed to tackle the climate crisis as laid out by the CCC recently, and fully expect the Scottish government to respond to that challenge".

Have emissions been falling?

The short answer is yes, but not by enough.

By 2021 greenhouse gas emissions had fallen by 49.2% compared with the baseline level in 1990.

That's a massive half of our planet warming gases which have already been eradicated from the economy.

But the law required a 51.1% fall by that date to keep on track.

Some industries have seen huge changes that have driven down emissions like the energy and waste sectors.

Others have remained stubbornly unmoved such as transport and agriculture.
What would scrapping the targets mean?

It is likely the Scottish government would replicate the system of "carbon budgets" used by both the UK and Welsh governments.

Rather than annual targets, ministers would be told how much greenhouse gas could "safely" be emitted during a parliamentary term and have to come up with a plan to achieve that.

It would mean an end to the legal requirement of successive environment secretaries having to explain to parliament why the targets have been missed.

There is an argument that the annual targets are a distraction because emissions are influenced by many factors including the weather and that the overall trend is more important.

Having been the first government in the world to declare a climate emergency, scrapping targets will be an embarrassing retreat.
What will the Scottish government do now?

Ministers have a conundrum; they are legally required to produce a "climate change plan" which details how they will achieve their targets.

That plan is now long delayed and the Climate Change Committee confirmed last month that the flagship 2030 target was now beyond reach.

So, it is just not possible to produce that plan any more.

An option would be to set new targets within the existing legislation and then produce a plan.

But one official described those annual targets as nothing more meaningful than a straight line on a graph.

So abolishing them altogether - and perhaps setting a lower 2030 target - seems the most likely course of action available.


Yousaf ‘will ditch Sturgeon’s pledge to cut Scotland’s greenhouse gases’

Simon Johnson
Wed, April 17, 2024 

Humza Yousaf and his Government were accused of over-promising and under-delivering - Michael McGurk


Humza Yousaf will dump Nicola Sturgeon’s flagship pledge of cutting Scotland’s greenhouse gases by 75 per cent by the end of the decade, it has been reported.

Ms Sturgeon said her SNP administration was a global leader on climate change when the target was introduced in 2019, calling it the “most stretching” in the world.

But in an embarrassing climbdown, Mr Yousaf’s SNP-Green government is expected to use a ministerial statement at Holyrood on Thursday to confirm that the 2030 target has been ditched. Harmful emissions were supposed to have been cut by three-quarters compared to 1990 levels.

BBC Scotland reported that a final goal of Scotland being net zero by 2045 – five years ahead of the rest of the UK – would remain, but that annual climate targets covering emissions from sectors such as transport and heating could also be scrapped.
‘Succession of missed targets’

The expected announcement comes after the UK’s official climate watchdog said last month that the current rate of progress in cutting greenhouse gases would have to be increased by a factor of nine for the 2030 target to be met.

In a damning report, the Climate Change Committee said this level of increase was “beyond what is credible” and was double the most ambitious scenario it had modelled if stringent measures were introduced.

The assessment found that Scotland’s annual target for cutting emissions was missed again in 2021 – for the eighth time in the last 12 years – after greenhouse gas levels rose by 2.4 per cent as the economy rebounded from the Covid pandemic.

The Tories said ditching the 2030 target would be an “abject humiliation” for the SNP and its Green coalition partners.

Douglas Lumsden, the Scottish Tories’ shadow net zero secretary, said: “For all the boasting about their supposed environmental credentials, the reality is a succession of missed targets – and being forced to throw in the towel on this flagship pledge represents the biggest failure of the lot.

“This climbdown is not a surprise, given the damning report from the Climate Change Committee, but it is symptomatic of a nationalist coalition that routinely over-promises and under-delivers.”
‘Scotland deserves better’

Michael Shanks, a Scottish Labour MP, wrote on X, formerly Twitter: “Defending the profits of oil and gas giants, now binning their key climate target. Clearly the Greens are having a strong influence in government. Scotland deserves better than this lot.”

The Scottish Government refused to confirm or deny whether the 2030 report would be scrapped, saying the details would be announced in the statement by Mairi McAllan, the SNP’s Net Zero Secretary.

The Climate Change Committee is an independent statutory body that advises the UK Government and devolved administrations on their emissions targets.

Just over 6,000 heat pumps were installed in Scottish homes last year, it said in last month’s report, but this “needs to increase to more than 80,000 per year by the end of the decade”.

The committee also noted that publication of the Scottish Government’s new draft climate change plan, which was supposed to have happened late last year, had been delayed. This meant there was “no comprehensive delivery strategy for meeting future emissions targets and actions continue to fall far short of what is legally required”.

CTHULHU STUDIES

Oldest known sex chromosome emerged 248 million years ago in an octopus ancestor

The oldest-known sex chromosome emerged in octopus and squid between 455 million and 248 million years ago — 180 million years earlier than the previous record-holder, scientists have discovered.

Octopus and squid appear to have evolved sex chromosomes at least 248 million years ago.

 (Image credit: Olga Visavi/Shutterstock)


The oldest known sex chromosome in animals has been discovered, pushing back the date for the evolution of sex chromosomes to between 248 million and 455 million years ago.

The ancient chromosome was found in octopus and squid, suggesting that these may have been among the first animals to determine their sex via genetic blueprint, instead of environmental cues.

Sex chromosomes are standard in mammals. In humans, the sex chromosomes are X and Y. Males usually have an X and a Y chromosome, while females have two Xs, although there are some variations, such as XXX or XXY, which can have a wide range of impacts from no effect at all to certain learning disabilities or neurological differences.

For a long time, researchers weren't sure whether cephalopods, the soft-bodied mollusks that include squid and octopuses, determined their sex with chromosomes. Mollusks have a variety of ways to handle reproduction, including hermaphroditism or sequential hermaphroditism, in which individuals swap sexes over time.

Octopuses stick to one sex, but it wasn't clear whether genes or environmental cues determined what sex that would be. In some reptiles and fish, factors like temperature decide the sex of offspring.

Related: Octopuses torture and eat themselves after mating. Science finally knows why.

In 2015, researchers completed the first full gene sequence of a cephalopod, the California two-spot octopus (Octopus bimaculoides). That sequence still included gaps, though, so a team led by Andrew Kern, a biologist at the University of Oregon, set about filling them in with high-fidelity sequencing.


Researchers discovered the chromosome after completing the full gene sequence of the California two-spot octopus. (Image credit: Brent Durand/Getty Images)

They soon noticed that one chromosome, chromosome 17, seemed less filled-out with genes than the other chromosomes in their sequence. Because they had sequenced a female octopus, they compared their results to the earlier individual, a male. In the case of the male, chromosome 17 looked no less populated than other chromosomes in the octopus.

This was a clue that chromosome 17 might have something to do with sex differences. To confirm, the team sequenced four more octopuses, two male and two female, and confirmed that females have just one copy of chromosome 17, while males have two. Thus, they represent the octopus sex chromosomes not as XY and XX as in humans, but as ZZ and Z0.

The researchers then compared their octopus genomes to the genomes of three other octopus species, three species of squid, and the chambered nautilus (Nautilus pompilius).

They found the ZZ/Z0 pattern in the squid and the octopus, but not in the nautilus, a more distantly related species. This showed that the sex chromosomes evolved after the split between the nautilus line and the line leading to modern squid and octopus, which occurred between 455 million and 248 million years ago.

"This is an astoundingly long time for a sex chromosome to be preserved," the researchers wrote in their paper, which is now available pre-peer review on the preprint website BioArxiv.

Prior to this research, the oldest confirmed sex chromosome was in sturgeon fish, according to Nature News, with an age of about 180 million years.

Octopuses Might Have The Oldest Sex Chromosomes in The Animal Kingdom

NATURE09 March 2024

ByCARLY CASSELLA

(Judit Pungor/CC By 4.0)

Cephalopods may have the oldest sex chromosomes of any animal, according to a recent discovery in the octopus genome.

That's a big deal given that scientists didn't know until now that these oddball creatures even had a form of sex determination written into their genes. To determine if an octopus is male or female, biologists have relied purely on observation, differentiating between which individuals lay eggs versus which produce sperm.

Searching the octopus genome had shown no clear sign of a sex chromosome system. Scientists were beginning to wonder if perhaps cephalopods were like some fish and reptiles, with sex determined through environmental factors such as the temperature at which eggs are kept rather than the inheritance of distinct chromosome.

At last, researchers at the University of Oregon claim to have solved the mystery.

Their pre-print study, which is currently under peer review, provides the first evidence of genetic sex determination among octopuses.

Examining the genes of the California two-spot octopus (Octopus bimaculoides) – the first cephalopod to have its whole genome sequenced – researchers have finally found a unique chromosome pair.

They discovered it on chromosome number 17, and it only stood out to researchers when they compared the male octopus genome that had been fully sequenced to a female one. The female octopus seemed to be missing one of their two copies.

Digging further, researchers say they found clear signatures of a ZW sex-determination system, which is seen in birds, crustaceans, and some insects,

We humans rely on an XY system, wherein two X chromosomes create the default female body plan, while the presence of a Y chromosome generally triggers the development of male characteristics.

Octopuses have an opposite system. It is the males that typically have a double-Z pair and females that have only one Z chromosome.

To see if this system was present in other cephalopods, researchers compared the genomes of three octopus species, three squid species, and a nautilus.

They concluded that the Z chromosome is an "evolutionary outlier" that stands apart from similar chromosomes in close relatives.

Only the genomes of the bobtail squid (Euprymna scolopes) and the East Asian common octopus (Octopus sinensis) had similar outlier signatures, but because these creatures are from different lineages, it suggests the Z chromosome originated before their split.

As such, researchers at the University of Oregon argue that the Z chromosome is "of an ancient, unique origin" that probably arose between 455 and 248 million years ago. If the chromosome appeared towards the earlier end of that timeline, the octopus could have the oldest animal chromosome yet found, beating even some insects which are thought to have sex chromosomes that date back 450 million years.

Compared to those of octopuses, however, these arthropod sex chromosomes are poorly conserved across species.

For comparisons, the oldest accepted vertebrate chromosome is that of a sturgeon fish, which is thought to be about 180 million years old. Sturgeon fish females have a ZW sex chromosome set pair as opposed to the female octopus's 'hemizygous' Z chromosome. It's possible the octopus's corresponding W chromosome may have been lost over time in a manner similar to the ill-fated trajectory of the Y chromosome in humans.

The story behind sex chromosomes has changed a lot in recent years. Once, they were thought to be intrinsic features of sex determination in animals. But biological research tends to be biased towards mammals. As it turns out, some fish and reptiles, like crocodiles, don't have sex chromosomes at all. The sex of their offspring is instead determined by other, external factors through epigenetic regulations.

Clearly, there is still much to be learned about how sex chromosome evolved, and why. Octopuses, with their deep evolutionary roots could be fascinating models for future research.

"The data presented in this paper definitely suggests that cephalopods have among the oldest sex chromosomes in both animals and plants," independent evolutionary scientist, Sarah Carey, told Carissa Wong at Nature.

"This is such a cool time to be working on the genetics of sex chromosomes."

The preprint was published in bioRxiv.

Oldest known animal sex chromosome

evolved in octopuses 380 million years ago


Result reveals for the first time how some cephalopods determine sex.

By Carissa Wong
04 March 2024

The California two-spot octopus (Octopus bimaculoides) has one or two copies of chromosome 17, depending on its sex.Credit: Norbert Wu/Minden Pictures via Alamy

Researchers have found the oldest known sex chromosome in animals — the octopus Z chromosome — which first evolved in an ancient ancestor of octopuses around 380 million years ago. The findings1 answer a long-standing question about how sexual development is directed in the group of sea creatures that includes octopuses and squid.

“We stumbled upon probably the oldest animal sex chromosome known to date,” says evolutionary geneticist Andrew Kern at the University of Oregon in Eugene. “Sex determination in cephalopods, such as squids and octopi, was a mystery — we found the first evidence that genes are in any way involved.”

How does it feel to have an octopus arm? This robo-tentacle lets people find out

In many animals, including most mammals and some insects, sex chromosomes determine whether an individual becomes male or female. In humans, females usually have two X sex chromosomes, and males typically have one X and one Y sex chromosome. But for some animal groups, such as cephalopods — which include soft-bodied animals such as squids and octopuses, as well as hard-shelled creatures called nautiluses — researchers have been unsure about how individuals become male or female. Scientists generally thought that environmental factors such as temperature play a part — as they do for some reptiles and fish.

Catching Zs

In 2015, researchers reported2 sequencing a cephalopod genome for the first time — that of a male California two-spot octopus, Octopus bimaculoides. In the latest study1, Kern and his colleagues mapped the genome of a female California two-spot octopus. They discovered 29 pairs of chromosomes and one single chromosome, called chromosome 17. By contrast, the male octopus genome had two copies of chromosome 17. That difference led the researchers to hypothesize that chromosome 17 was a sex chromosome.

Sequencing the DNA of other O. bimaculoides octopuses confirmed the idea. Males always had two copies of chromosome 17, whereas females had one copy. Chromosome 17 also contained several genes similar to those that encode proteins in human reproductive tissues, including a protein found in sperm. In animals including birds and butterflies, males similarly have two Z sex chromosomes, whereas females have one Z and one W sex chromosome.

“It very much looked like we were looking at a Z chromosome in O. bimaculoides,” says Kern. But the researchers failed to find a W chromosome in the female octopuses. That suggested that males have ZZ sex chromosomes, whereas females are ZO, with the O denoting the lack of a W chromosome.

Well conserved

The team also found Z chromosomes in some other octopus and squid species — but not in a nautilus.

“This pattern suggests that the Z chromosome evolved once in the lineage that led to modern squid and octopuses — after this lineage split off from hard-shelled nautiloids,” says Kern. This means the Z chromosome first appeared between 450 million and 250 million years ago and has been retained to the present day, he says. Previously, the oldest known animal sex chromosome was thought to have evolved in sturgeon fish about 180 million years ago3.

This chromosome is profoundly evolutionarily conserved, says Matthias Stöck, an evolutionary geneticist at the Leibniz-Institute of Freshwater Ecology and Inland Fisheries in Berlin.

“The data presented in this paper definitely suggests that cephalopods have among the oldest sex chromosomes in both animals and plants,” says Sarah Carey, who studies the evolution of sex chromosomes at the HudsonAlpha Institute for Biotechnology in Huntsville, Alabama. “This is such a cool time to be working on the genetics of sex chromosomes.”

doi: https://doi.org/10.1038/d41586-024-00637-0

References

1. Coffing., G. C. et al. Preprint at bioRxiv https://doi.org/10.1101/2024.02.21.581452 (2024).

2. Albertin, C. B. et al. Nature 524, 220–224 (2015).

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3. Kuhl, H. et al. Phil. Trans. R. Soc. B 376, 20200089 (2021).