Wednesday, 27 February 2019

Climate change >>> an early spring and upsetting the balance of nature

Two weeks ago, the news was how insect populations are collapsing - and that climate change is one of the key factors:
Worldwide decline of the entomofauna: A review of its drivers - ScienceDirect
Plummeting insect numbers 'threaten collapse of nature' | Environment | The Guardian

From the weekend, here's a piece looking at the science behind the numbers - and how little we actually know: 

Amid recent warnings of the mass extinction of insects in the coming decades, the global lack of research into insect populations has come into focus.

The science of insect population collapse

By Alex McKinnon.

Last week, an article in the scientific journal Biological Conservation made waves around the world. Its authors, who reviewed 73 studies of insect populations, claimed they found “dramatic rates of decline that may lead to the extinction of 40 per cent of the world’s insect species over the next few decades”, triggering “wide-ranging cascading effects within several of the world’s ecosystems”. Headlines warned of an oncoming “insect Armageddon”. Google searches for the phrase “insects dying” jumped tenfold in a week.

Entomologists are not used to this kind of attention. The study of bugs is not the most glamorous or media-friendly of the scientific disciplines. When journalists do come calling, it’s often in response to a study that’s been blown out of proportion, or with a less-than-rigorous scientific basis. They have spent a lot of time recently talking down excitable people.

With the caution typical of researchers, they invariably start by mentioning the limitations of Biological Conservation’s article. Its authors mainly looked at studies conducted in Europe and the United States, making it difficult to infer worldwide conclusions. They found their 73 studies by searching “insect* + decline* + survey” in the online Web of Science database, potentially excluding studies that found evidence of increasing or stable insect populations. Sweeping conclusions such as “all the world’s insects are dying” can’t be drawn from one paper review, no matter how rigorous.

But none of the entomologists speaking on this study dismiss the Biological Conservation article as junk science. While it’s not a one-stop confirmation of the oncoming insect apocalypse, it confirms what smaller, single-location studies have found in the past. Several entomologists argue that the article’s greatest value lies in the gaps it revealed: the studies it couldn’t draw on, the research that was never funded.

Dr Manu Saunders is a postdoctoral research fellow at the University of New England, specialising in insect ecology. She says that while the attention on her often-neglected field is welcome, the media’s treatment of the Biological Conservation article – and scientific issues in general – obscures an even more serious problem: we don’t know nearly enough about the world’s insects to tell if we’re killing them.


The science of insect population collapse | The Saturday Paper

With things particularly acute in Australasia:
Climate change: Dropping insect numbers ‘threaten collapse of nature' - news.com.au
Climate change is killing off Earth’s insects | Stuff.co.nz
Decline in bogong moth numbers could have catastrophic effects in the Australian Alps - Science News - ABC News

Meanwhile back in the UK, there are fears that the unusually early spring will cause further havoc:
Naturalists concerned for early-emerging spring species in UK | Environment | The Guardian

These fears have been voiced every year recently: 
Futures Forum: Climate change >>> is spring happening earlier or later? (2018)
Futures Forum: Climate change >>> Shifting Spring @ Costing the Earth on Radio 4 (2018)
Futures Forum: Climate change: Spring advancing at an 'eye-opening' pace (2017)
Futures Forum: Climate change: 'season creep' and an early spring (2016)
Futures Forum: Spring has sprung... notably the bluebell and the dandelion ... and spring has sprung early ... (2014) 

The Independent reports today:

What is the impact of hot winter weather and is climate change playing a role?

‘None of this is normal - while nature can adapt to seasonal fluctuations it can be dangerous if it keeps happening’

Harry Cockburn
13 hours ago


Hedgehogs could struggle for food, frog spawn could be lost to frost and birds could suffer if they migrate early, experts have warned as the UK is experiences the highest winter temperatures since records began over a hundred years ago.

A temperature of 21.2C was recorded at Kew Gardens in London on Tuesday, beating the 20.6C measured at Trawsgoed, near Aberystwyth the day before. The soaring temperatures have been described as “an extreme weather event” by the Met Office and come at the end of a particularly mild winter.

Met Office spokesman Grahame Madge told The Independent: “To see temperatures of over 20 on a winter’s day is exceptional. The previous record was 19.7 and that’s stood since 1998. It is a rare event to see temperatures this high in February."

While February is now “within striking distance” of becoming the warmest February since records began, December was also two degrees warmer than average overall, with high temperatures early in the month reaching over 15C.

Meanwhile, 27 councils across the country have declared a “climate emergency” in an effort to force authorities to act against climate change.

Later this week the heat is expected to drop somewhat as an Atlantic weather system brings strong wind and rain.

The effects of the unseasonably warm weather are felt particularly keenly at this time of year by hibernating animals, who may emerge earlier and find there is not enough food to sustain them, and that the weather may turn cold again.

“It is mammals who will suffer worst,” Ben Keywood, an entomologist at Sheffield & Rotherham Wildlife Trust told The Independent. “If hedgehogs have started coming out over the last two weeks or so, they are going struggle to find a lot of the food they would normally eat as a lot of it is not out yet. So then [when the temperature falls] they may not have had enough to eat when they go back into hibernation and will have used up more of their fat reserves, which can make them significantly weaker.

“Frogs could also start to spawn, and that wouldn’t normally happen until March or April, if they spawn and then there is a frost, then it could kill all the spawn, which would be disastrous.”

The concern, he said, was that if climate change makes this a more regular occurrence and this keeps happening “then it could start having very severe effects on species because it can weaken them and change their behavioural patterns”.

He added: “Lots of species time their emergence - particularly birds - so it coincides with the food they need is at its most plentiful,” he said. “So if that starts early then they are out of sync with their food source. It could help species such as owls and birds of prey, as [species like dormice and harvest mice] will be more visible, and could be weaker.”

“It’s all about upsetting the balance - none of this is normal. While nature can and will adapt to seasonal fluctuations, it does send things off kilter and can be dangerous if it keeps happening.”

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