Gary Haq: What the big freeze tells us about our shifting climate

WITH snowfall, sub-zero temperatures, ice, fog and treacherous conditions on the roads bringing the country to a halt, it is hard to believe that global warming is really happening.

Yet 2010 has seen global temperatures rise to near record levels. According to the Met Office, provisional global temperature figures have put 2010 on track to become the first or second warmest on record.

This is despite a declining El Nio, a climatic phenomenon that is characterised by unusually warm temperatures, being replaced by La Nia, which has had a strong cooling effect.

Climate sceptics are quick to point to the recent big freeze as evidence to suggest that climate change is a load of baloney.

However, many people fail to make the distinction between climate – the average weather patterns over years – and weather, which is a series of short-term events that can change dramatically from one day to the next.

The big freeze is a mere blip in the overall long-term trend that has seen global temperatures rise. So what has been the cause of the recent cold weather?

A study by the University of Reading has linked the unusual cold winters in northern Europe to periods of low sunspot activity and atmospheric conditions that "block" warm westerly winds.

Changes in the fast -moving winds in the upper atmosphere, known as jet streams, can have a major influence on weather. Jet streams normally bring mild, wet and westerly winds that cause the winter weather we have come to expect.

However, when the jet stream is blocked, it forms an "s" shape over the northeastern Atlantic, causing the wind to fold back on itself. This pushes the jet stream further northwards allowing cold, dry easterly winds to flow over Europe which results in a sharp fall in temperature.

The phenomenon of "blocking" only affects a limited geographical area and its impact is dependent on a number of conditions being met before it occurs.

Allowing for climate change, European winters have been 0.5 degrees Celsius colder than average during years of low solar activity.

The winter of 2009 was England's 18th coldest in 350 years even though the global temperatures were the fifth highest. It still unclear why changes in solar activity affects weather patterns, which indicates that we still have a lot to learn about the complex interactions and feedback loops that characterise the climate system.

Throughout history, we have feared and revered the weather and have tried to make sense of this natural phenomenon that has such a powerful influence on our way of life.

The weather has not only played a role in shaping our physical environment such as our landscape and coastline, it has fashioned our cultural identity.

It influences how we feel, how we spend our leisure time, how we socialise, how we work and what we wear.

We have become notorious throughout the world for our obsession with the weather. British weather is so variable and unpredictable throughout the year; it is not surprising that we talk so much about it.

Unlike climate change that remains a controversial issue, the weather is a safe topic of conversation which we happily discuss with total strangers and use to avoid sensitive or personal matters.

There was a time when we use to look to the skies and believed that the weather was determined by some higher being, a time when we tried to predict the weather by observing changes in the natural environment.

Today we look down to the latest application on our mobile phone to get weather forecasts based on observations using instruments analysed with the aid of computers.

Yet, despite advances in science and technology that has allowed us to control nature, we still remain vulnerable to extreme weather events.

Last week 190 nations met in Cancun, Mexico to discuss the international response to the challenge of climate change.

The meeting was successful in producing an agreement which outlines a near global consensus to take urgent action to curb greenhouse gas emissions. Acknowledging the rich world's historical responsibility for climate change, the Cancun Agreement establishes mechanisms for transferring funds from rich countries to poor counties to spend on climate protection.

However, it does not provide legally binding emission targets and only urges rich nations to do more. While the Agreement has saved the negotiation process, it has yet to save the climate.

Nevertheless, campaigners believe the foundation has now been set to provide a more comprehensive agreement at the next round of climate talks.

If we are to avoid any disruption of the climate system on which we are so naturally dependent, we need to take action sooner rather than later. The lessons from the last few weeks should have taught us that the weather is King and has the ability to bring the whole country to its knees in a matter of hours – we ignore its power at our peril.

Dr Gary Haq is a human ecologist at the Stockholm Environment Institute at the University of York.