Tony Deyal
IN THE last century, our planet's average temperature has risen by over half a degree celsius. Earlier springs, melting ice and rising sea levels have all been blamed on climate change. But couldn't these signs just be a blip in the stats? No.
Most scientists now agree that the Earth's climate is changing. It's not just because of better measurements or data collection. And the changes have been seen for long enough to satisfy even most sceptics that the change is real. Doesn't the climate vary naturally? Yes the Earth's climate swings naturally from ice age to jungle warmth. But it's usually an incredibly slow process.
It takes massive global changes to cause an ice age. One theory suggests that when continents drift into one another, pushing huge areas of land to higher altitudes, the surrounding ocean and atmospheric patterns change radically. This time, our climate isn't following the rules of previous slow-moving changes. What's different this time? We're changing the make-up of our atmosphere by burning fossil fuels and increasing carbon dioxide emissions. And this is causing the climate to change faster than ever before, overwhelming the planet's natural balancing mechanisms. When we change our planet beyond recognition, experts say we'll only have ourselves to blame.
PAST CHANGES
How have people coped with climate change in the past? Not very well even when it's been slow and natural. In the 15th century, temperatures in Greenland dropped by two degrees celsius through natural climate variation. Viking communities that had settled in Greenland saw their livestock die and weren't able to go fishing because of the increase in sea ice. In Britain the cooler temperatures drastically reduced the area of land that was suitable for wheat cultivation.
Isn't it getting hotter this time?
Warmer climates in the past have affected life on Earth just as radically. Satellite images show ancient riverbeds in the Sahara now the world's largest desert. Archaeologists have found evidence that hippopotamuses lived in the region until 4000 years ago, when the rivers dried up.
CLIMATE PROBLEMS
If our climate's changing, what's the problem anyway? Since the last ice age ended 10,000 years ago, our climate has been relatively stable. But all that's changing now. The global average temperature has risen by 0.6 ºC in the last 100 years. If it continues to rise as predicted, future warming could happen faster than ever before.
Why don't we just do something to stop it? We can't easily change the climate or stop it from changing in the future. It's too late to stop the climate change that's now occurring as a result of increased carbon dioxide emissions in the 20th century. But if we change our fuel-thirsty lifestyles now, we may be able to slow down the effects and learn to adapt better to change in the future.
GLOBAL COSTS
But we're not yet ready to face the consequences of climate change. Higher global temperatures are already affecting our world - 20 million people are currently threatened with flooding in Bangladesh. The world economy is also at risk. The cost of dealing with the effects of climate change is spiralling towards $300 billion every year.
Why should I care? The climate affects where we live, how we live, what we wear, what we eat, what we grow, as well as our health and our economy. Climate change gives us a choice: should we change our lifestyle to preserve what we can of our current climate? Should we face the consequences and try to adapt? Or do we need to do both if we're to cope?
What is causing climate change today? We've upset our planet's delicate balance of energy inputs and outputs. Since the 1700s, emissions produced by our burning of fossil fuels have been altering the composition of the atmosphere. Too much greenhouse gas means too much of the Sun's energy gets trapped in our atmosphere, heating up the planet.
So what are greenhouse gases? Carbon dioxide, methane, nitrous oxides, ozone and water vapour are all greenhouse gases found in our atmosphere. They trap heat close to the Earth's surface. But their levels are rising fast. By burning fossil fuels to sustain our modern lifestyle, we pump billions of extra tonnes of carbon dioxide into the environment. By 2100, its concentration in the atmosphere will likely be two or three times higher than the level in 1750.
What's the greenhouse effect? The greenhouse effect is a natural feature of the Earth's environment, keeping our planet's surface at a warm average temperature of 15 C. Most of the Sun's energy that reaches the Earth's surface is absorbed and re-emitted as heat. Greenhouse gases in the atmosphere trap some of the rising heat, radiating it back to the planet's surface. Without the greenhouse effect, the average temperature would plummet to -18 C - too cold for most life.
RISING HIGH
How do greenhouse gases influence climate change? The higher the concentration of greenhouse gases in the atmosphere, the stronger the greenhouse effect. Scientists now agree that there is evidence that most of the warming seen over the last 50 years can be blamed on human activities. During the twentieth century the average surface temperature of the Earth rose by 0.6 C.
Which nations are the worst polluters? Top of the list of climate sinners is the United States. It has 5 per cent of the world's population, but accounts for 24 per cent of global carbon dioxide emissions. But other industrialised nations are not saints either. In terms of amounts of carbon dioxide emitted per person, western European countries, Australia and Japan are also significant contributors.
What's America's problem? The US government feels that the country's economy will be unfairly hit by Kyoto commitments. But Alden Meyer of the Washington DC-based Union of Concerned Scientists (UCS) says President George Bush has just given in to what the oil and coal industries want. Of the world's major polluters, EU countries, Russia and Japan have agreed to make emission cuts. China and India belong to a group of developing countries not yet required to make cuts.
What about developing countries? The developing world has until now been responsible for only 25 per cent of global emissions. But a few highly populated countries in the developing world, including India and China, are now in the top ten of global baddies. Per person, however, developing countries' carbon dioxide emissions are still way below those of the industrialised world.
DOING THEIR BIT
But who's actually doing the most to combat climate change? A total of 178 countries (including 39 industrialised nations) signed up to the Kyoto Protocol in 2001. A first wave of countries has agreed that, by 2012, they'll cut their greenhouse gas emissions by an average of two per cent compared to their 1990 levels. It's less than many originally hoped, and much less than many scientists say is needed. And the United States, the world's largest emitter, has not come on board.
How can we make any difference? If we're going to reduce carbon dioxide levels in our atmosphere, we need to cut world emissions by half, scientists estimate. But the USA hasn't signed up to the Kyoto protocol - the 1997 agreement between 39 industrialised nations to cut carbon dioxide emissions. And it doesn't seem fair to expect developing nations to hold back in their efforts to increase standards of living.
So what's the answer? While we wait for political action, individuals can make a difference. Small actions taken by millions of people at home, at work, while shopping, cooking or travelling could change the world for the better. There'll be a time lag, but we'll make a difference.
Hang on - how do you stop climate change anyway? The crucial factor in halting climate change is reducing levels of carbon dioxide in the atmosphere.
It may be invisible, odourless and tasteless, but this gas stops heat escaping from Earth to space - warming our world way beyond what's normal and affecting our climate. By burning fossil fuels to power factories, cars and homes, we add to the build-up of carbon dioxide.
For further information please contact Tony Deyal at tdeyal@yahoo.co.uk, Climate Change Centre, Central Campus, University of Belize, Belmopan, Belize C.A.
