Climate Change

The World’s climate is always changing. Climate is not static - it is always changing from year to year and from place to place. In some years Summer will be hotter than others, and in some years Winter will be colder. This year (2007) in the UK the month of April was much hotter than normal, whereas May was much wetter than normal. These variations are all short term and localised, and should not in themselves be cause for concern.

Longer term trends are more significant. Scientists have been measuring the world’s climate trends accurately since 1850. Prior to this they have used a wide range of indicators (“proxies”) such as ice cores and tree rings to create a picture of trends from the past. Taken together these values show that the world’s climate has slowly fluctuated over the centuries.

Speed of change is the big issue. The main reason that scientists have become greatly concerned about recent climate change is the unprecedented rate and degree of change in global temperatures. The world appears to be entering “uncharted territory”.

The Earth IS warming up. There is no debate whatsoever about the fact that the world is getting warmer - much warmer - and that the trend is accelerating.

Why is it happening?

The world’s climate is very complex. There are a large number of factors that influence climate. These include variations in the sun’s radiation, changes in the earth’s surface (such as the amount of ice and vegetation cover), and the constituent components of the atmosphere. These are collectively called “forcings” and climate scientists have studied their characteristics and interactions in great detail.

The “greenhouse effect” has enabled life to exist on Earth. The greenhouse effect was first discovered in 1829 and is the term used to describe the way in which the Earth’s atmosphere acts to retain heat from the Sun. Without this effect the Earth would be 20-30ºC colder and life would not have developed in the way it has. This is a very well understood mechanism based on solid science, and the degree to which heat is retained is determined by the amount and proportion of “greenhouse gases” in the atmosphere.

The proportion of greenhouse gases in the atmosphere is changing. The proportion of different greenhouse gases in the atmosphere has continually fluctuated, and this has been part of the reason that the Earth’s climate has varied over time. However there have been two very significant unnatural changes over the past two hundred years. One is the vast increase in the world’s human population, and the second is the discovery and use of fossil fuels to produce cheap energy. These have together resulted in a dramatic increase in the introduction of greenhouse gases into the atmosphere.

Scientists have modelled the effect of all the influences on the climate. Many different computer models have been developed based on the well-established physical characteristics of the constituent influences on the climate. These all show remarkable agreement in their representation of the contribution of the different elements to past changes in the Earth’s climate.

The speed of current change is a key factor. With every year it becomes clearer that the divergence of the curve from previous trends can only be explained by an ever-increasing effect from greenhouse gas emissions.

Why should we do something about it?

The stability of the Earth is threatened. We are all used to the Earth providing a stable environment for us to live in. Within the last two thousand years temperatures have only varied relatively moderately, and this has meant that our way of life has been able to evolve and develop progressively without any great constraints from the world around us.

The Earth may not always be as it is now. Land areas have remained fairly constant and availability of basic resources such as water and food have all been sufficient in the past. However we can no longer take this for granted if global temperatures increase significantly. And the indications are that this is now happening at a faster pace than ever before, and projections are that this pace will accelerate further unless we do something about it.

Scientists are concerned about “Tipping Points”. As the Earth’s temperature increases there is a great risk that certain changes will have a “positive feedback” effect on climate change. For example, as the ice cover on the poles reduces the amount of the Sun’s radiation that is reflected back into space will decrease, further increasing the warming of the atmosphere. There are also concerns that large amounts of greenhouse gases which are currently locked away will be released, rapidly increasing the proportion of greenhouse gases in the atmosphere with potentially catastrophic effect.

The Earth will survive but mankind might not. The Earth can always change its state into another form and nature will adapt. But its new form may not be conducive to survival for humankind, or at least not in its current numbers.

What can we do about it?

Energy from fossil fuels may be cheap in money terms but it’s costing the Earth. Ever since we discovered fossil fuels the only measure that has been employed to limit their use is their financial cost. However there is another cost - their impact on the environment. The only way of mitigating this is to significantly reduce their use. This is entirely possible without altering our way of life to any great degree, although the longer we leave it before reducing our wastage of energy the greater the impacts on our lifestyles will be.

Lifestyle choices make a big difference If everyone buying a new car were to purchase one with fuel efficiency of 40mpg or better (rather than maybe a Range Rover or similar that only does 15mpg), ensure that their house has maximum insulation to reduce energy loss, switch all light bulbs to low energy types, buy as many locally sourced goods as possible, throw away as little as possible, reduce use of fresh water, and so on (see our leaflet on “40 Top Tips for reducing your Carbon Footprint”), the nation’s carbon emissions could very quickly be significantly reduced through greater energy efficiency.

Fossil fuels won’t last for ever. It is also in our interests to make sure that we use what is left as efficiently as possible, quite apart from their impact on Climate Change. Some projections suggest that the world only has 30-50 years of oil left, and shortages will start to have an effect on prices long before then. But sadly this effect will not be sufficient by itself to reduce emissions by as much as is needed to avoid the worst effects of Climate Change.

Governments needs to take a lead. There is great value in everyone taking as many steps as possible right now to reduce their emissions. But ultimately it will need Governments to take a lead in this to encourage us all to act together before everyone plays their part. We should all exhort Governments to do this on our behalf so that they know that we are behind them in saving the Earth from the worst effects of Climate Change.

Britain only causes 2% of the world’s emissions. But we only have 1% of the World’s population so we are already creating twice our fair share of emissions. It is impossible to get other countries, such as China and India, to reduce their emissions when we are responsible for so much more per person than they are.

Be very wary of the “Sceptics”. The arguments of most sceptics are generally based on anecdote, highly dubious or distorted science, and clutching at straws. Most sceptics simply don’t want Climate Change to be happening as a result of our collective actions because they don’t want to have to change their lifestyle in any way, or because they have a financial incentive to not believe in it, or the solid science behind it. This is obviously not a mature and rational basis on which to decide something as serious as whether or not to take action against climate change.