Wind farms and abuse of statistics: bird edition

When "wind farms are dangerous" really just means "there are a lot of birds".

When dealing with large numbers, it helps to have an idea of the expected order of magnitude. That way, you can know whether it is merely the number which is large, or the thing it's describing as well.

For instance, if I tell you of a country with 140,000 people in long-term unemployment, it's rather important for you to know if I'm talking about the US (population 280 million) or Luxembourg (population 525,000).

That's a test a Spectator article, Wind farms vs wildlife, failed quite badly this week.

The author, Clive Hambler, is a lecturer in biological and human sciences at Oxford university, and quotes a number of statistics to demonstrate how dangerous wind farms are to wildlife. For instance:

Every year in Spain alone — according to research by the conservation group SEO/Birdlife — between 6 and 18 million birds and bats are killed by wind farms. They kill roughly twice as many bats as birds. This breaks down as approximately 110–330 birds per turbine per year and 200–670 bats per year. And these figures may be conservative if you compare them to statistics published in December 2002 by the California Energy Commission: ‘In a summary of avian impacts at wind turbines by Benner et al (1993) bird deaths per turbine per year were as high as 309 in Germany and 895 in Sweden.’

Similar claims are made throughout. Apparently the annual death toll of bats in the US and Canada is "up to three million", "Norwegian wind farms kill over ten white-tailed eagles per year", and so on.

What is missing is any context through which we can examine these numbers. It might change our interpretation of the figures to know that:

Domestic and feral cats have also been considered a major source of anthropogenic-caused mortality with estimates near 100 million annual bird deaths [in the US].

Or that, on roads near wetlands in Canada:

223 birds were killed per mile per year.                                                                                            

Power lines in the US are estimated to kill:

…approximately 130 million birds per year.                                                                                                        

While we're banning things, we may want to keep an eye out for that scourge of the avian world, windows:

97.6 to 976 million bird deaths per year in the U.S. due to collisions with windows… based on an estimated 1 to 10 bird deaths per structure per year from a fatality study in New York.

All those figures come from a 2005 paper by the US Department of Agriculture.

In other words, even with the massive figures from Spain – figures which show deaths per turbine per year two orders of magnitude higher than equivalent figures cited in the above paper, which are based on an assumption that for every confirmed death, there's nineteen uncomfirmed, and which come from a set of guidelines which explicitly concludes wind farms are OK for birds if built correctly (pdf) –  wind farms kill fewer birds than cats, power lines, roads or windows. That comparison would have been rather useful to include in the original piece. With that in mind, the numbers in the piece become less a demonstration of the awesome mortality of wind farms, and more a confirmation that yes, there are a lot of birds in the world.

Update

It's been pointed out on Twitter that I'm not comparing like to like. Spain is smaller than the US, of course. Thankfully, the USDA also estimates the number of birds killed by wind farms in America: between 20,000 and 37,000 a year. I let you draw your own conclusions from the discrepancy.

Wind Turbines in Spain. Photograph: Wikimedia Commons

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

Photo: Getty
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George Osborne's mistakes are coming back to haunt him

George Osborne's next budget may be a zombie one, warns Chris Leslie.

Spending Reviews are supposed to set a strategic, stable course for at least a three year period. But just three months since the Chancellor claimed he no longer needed to cut as far or as fast this Parliament, his over-optimistic reliance on bullish forecasts looks misplaced.

There is a real risk that the Budget on March 16 will be a ‘zombie’ Budget, with the spectre of cuts everyone thought had been avoided rearing their ugly head again, unwelcome for both the public and for the Chancellor’s own ambitions.

In November George Osborne relied heavily on a surprise £27billion windfall from statistical reclassifications and forecasting optimism to bury expected police cuts and politically disastrous cuts to tax credits. We were assured these issues had been laid to rest.

But the Chancellor’s swagger may have been premature. Those higher income tax receipts he was banking on? It turns out wage growth may not be so buoyant, according to last week’s Bank of England Inflation Report. The Institute for Fiscal Studies suggest the outlook for earnings growth will be revised down taking £5billion from revenues.

Improved capital gains tax receipts? Falling equity markets and sluggish housing sales may depress CGT and stamp duties. And the oil price shock could hit revenues from North Sea production.

Back in November, the OBR revised up revenues by an astonishing £50billion+ over this Parliament. This now looks a little over-optimistic.

But never let it be said that George Osborne misses an opportunity to scramble out of political danger. He immediately cashed in those higher projected receipts, but in doing so he’s landed himself with very little wriggle room for the forthcoming Budget.

Borrowing is just not falling as fast as forecast. The £78billion deficit should have been cut by £20billion by now but it’s down by just £11billion. So what? Well this is a Chancellor who has given a cast iron guarantee to deliver a surplus by 2019-20. So he cannot afford to turn a blind eye.

All this points towards a Chancellor forced to revisit cuts he thought he wouldn’t need to make. A zombie Budget where unpopular reductions to public services are still very much alive, even though they were supposed to be history. More aggressive cuts, stealthy tax rises, pension changes designed to benefit the Treasury more than the public – all of these are on the cards. 

Is this the Chancellor’s misfortune or was he chancing his luck? As the IFS pointed out at the time, there was only really a 50/50 chance these revenue windfalls were built on solid ground. With growth and productivity still lagging, gloomier market expectations, exports sluggish and both construction and manufacturing barely contributing to additional expansion, it looks as though the Chancellor was just too optimistic, or perhaps too desperate for a short-term political solution. It wouldn’t be the first time that George Osborne has prioritised his own political interests.

There’s no short cut here. Productivity-enhancing public services and infrastructure could and should have been front and centre in that Spending Review. Rebalancing the economy should also have been a feature of new policy in that Autumn Statement, but instead the Chancellor banked on forecast revisions and growth too reliant on the service sector alone. Infrastructure decisions are delayed for short-term politicking. Uncertainty about our EU membership holds back business investment. And while we ought to have a consensus about eradicating the deficit, the excessive rigidity of the Chancellor’s fiscal charter bears down on much-needed capital investment.

So for those who thought that extreme cuts to services, a harsh approach to in-work benefits or punitive tax rises might be a thing of the past, beware the Chancellor whose hubris may force him to revive them after all. 

Chris Leslie is chair of Labour's backbench Treasury committee.