Steve Connor: This isn't just natural variation – it's caused by global warming

What people forget is that sea ice is not fixed to the ground, it is easily blown about

Share
Related Topics

A few years ago, just after the Arctic sea ice had retreated to its (then) all-time record in September 2007, I found myself in the company of a distinguished scientist and polar explorer who had taken a rather sceptical line on global warming. In short, he thought it was all a hoax.

Rising to the bait, I asked him what he thought about one of the most obvious manifestations of a warmer world, the continuing retreat of the Arctic sea ice in the summer months. How do you explain that? I asked him.

Simple, he said. The sea ice varies naturally and what we are seeing is well within the bounds of natural variability. What people forget, he added, is that sea ice is not fixed to the ground, it is easily blown about by the winds, making it seem as if it has disappeared when in fact it is just piled up on top of itself.

Although winds do affect the floating sea ice, there is little dispute about the satellite observations showing the extent of its retreat in recent decades. The US military satellites used by the US National Snow and Ice Data Centre in Boulder, Colorado, use passive microwaves to measure sea ice cover and they show a clear decline in surface area of more than 30 per cent since records began in 1979. But could such a significant decline be the consequence of natural variability?

Computer models of global warming suggest that sea ice would be one of the most obvious consequences of a warmer world, but these models did not predict that the observed decline would be quite so rapid.

Earlier this year, scientists from the Max Planck Institute for Meteorology in Hamburg tried to address this question of natural variability – looking at the impacts of seasonal variations in the weather and conditions such as the direction and strength of the Arctic winds.

Instead of using computer models, the scientists crunched the numbers on statistical associations to determine whether a particular phenomenon could be one of the causes behind the observed decline in sea ice.

While variable winds and weather can have dramatic effects on sea ice, they on their own could not explain the intensity of the observed decline, the scientists said. They also discounted other variables, such as solar radiation, cosmic rays, volcanic eruptions and oceanic heat transport. In the end, the only thing they were left with was the rising levels of CO2 in the atmosphere caused by human activities.

Their conclusion: the disappearing sea ice was indeed the manifestation of man-made global warming.

React Now

Latest stories from i100
Have you tried new the Independent Digital Edition apps?
SPONSORED FEATURES
iJobs Job Widget
iJobs General

Recruitment Genius: Office / Sales Manager

£22000 - £32000 per annum: Recruitment Genius: Established and expanding South...

Recruitment Genius: Administrative Assistant / Order Fulfilment

£14000 per annum: Recruitment Genius: An exciting opportunity to join a thrivi...

SThree: Trainee Recruitment Consultant

£18000 - £23000 per annum + Uncapped OTE: SThree: Trainee Recruitment Consulta...

SThree: Trainee Recruitment Consultant

£18000 - £23000 per annum + Uncapped OTE: SThree: Trainee Recruitment Consulta...

Day In a Page

Read Next
 

Syria's Kurds have little choice but to flee amid the desolution, ruins and danger they face

Patrick Cockburn
A bartender serves two Mojito cocktails  

For the twenty-somethings of today, growing up is hard to do

Simon Kelner
Refugee crisis: David Cameron lowered the flag for the dead king of Saudi Arabia - will he do the same honour for little Aylan Kurdi?

Cameron lowered the flag for the dead king of Saudi Arabia...

But will he do the same honour for little Aylan Kurdi, asks Robert Fisk
Our leaders lack courage in this refugee crisis. We are shamed by our European neighbours

Our leaders lack courage in this refugee crisis. We are shamed by our European neighbours

Humanity must be at the heart of politics, says Jeremy Corbyn
Joe Biden's 'tease tour': Could the US Vice-President be testing the water for a presidential run?

Joe Biden's 'tease tour'

Could the US Vice-President be testing the water for a presidential run?
Britain's 24-hour culture: With the 'leisured society' a distant dream we're working longer and less regular hours than ever

Britain's 24-hour culture

With the 'leisured society' a distant dream we're working longer and less regular hours than ever
Diplomacy board game: Treachery is the way to win - which makes it just like the real thing

The addictive nature of Diplomacy

Bullying, betrayal, aggression – it may be just a board game, but the family that plays Diplomacy may never look at each other in the same way again
Lady Chatterley's Lover: Racy underwear for fans of DH Lawrence's equally racy tome

Fashion: Ooh, Lady Chatterley!

Take inspiration from DH Lawrence's racy tome with equally racy underwear
8 best children's clocks

Tick-tock: 8 best children's clocks

Whether you’re teaching them to tell the time or putting the finishing touches to a nursery, there’s a ticker for that
Charlie Austin: Queens Park Rangers striker says ‘If the move is not right, I’m not going’

Charlie Austin: ‘If the move is not right, I’m not going’

After hitting 18 goals in the Premier League last season, the QPR striker was the great non-deal of transfer deadline day. But he says he'd preferred another shot at promotion
Isis profits from destruction of antiquities by selling relics to dealers - and then blowing up the buildings they come from to conceal the evidence of looting

How Isis profits from destruction of antiquities

Robert Fisk on the terrorist group's manipulation of the market to increase the price of artefacts
Labour leadership: Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea

'If we lose touch we’ll end up with two decades of the Tories'

In an exclusive interview, Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea
Tunisia fears its Arab Spring could be reversed as the new regime becomes as intolerant of dissent as its predecessor

The Arab Spring reversed

Tunisian protesters fear that a new law will whitewash corrupt businessmen and officials, but they are finding that the new regime is becoming as intolerant of dissent as its predecessor
King Arthur: Legendary figure was real and lived most of his life in Strathclyde, academic claims

Academic claims King Arthur was real - and reveals where he lived

Dr Andrew Breeze says the legendary figure did exist – but was a general, not a king
Who is Oliver Bonas and how has he captured middle-class hearts?

Who is Oliver Bonas?

It's the first high-street store to pay its staff the living wage, and it saw out the recession in style
Earth has 'lost more than half its trees' since humans first started cutting them down

Axe-wielding Man fells half the world’s trees – leaving us just 422 each

However, the number of trees may be eight times higher than previously thought
60 years of Scalextric: Model cars are now stuffed with as much tech as real ones

60 years of Scalextric

Model cars are now stuffed with as much tech as real ones