The Earth's climate has always varied, so the term climate change is now generally used to describe the changes caused by human activity - specifically, greenhouse emissions such as carbon dioxide and methane, which build up in the atmosphere and trap heat.
Is it the same as global warming?
As human activity increases the concentration of these gases in the atmosphere far beyond their natural levels, means that much more heat is trapped. Hence, the term climate change is often used interchangeably with global warming but the term 'global warming' is most certainly not a technicaly accurate term, because 'global warming' causes more extreme weather conditions and these will vary depending on the location. The winters may be longer and colder in one country or countries while rain becomes heavier, causing floods in others. At the same time droughts will take place in other parts of the world. The problem is that people confuse 'weather' (local) with 'climate' (world-wide).
Can it be explained by natural causes?
Earth's surface measurement show that average temperatures have increased by 0.4C since the 1970s, scientists are confident this change can be blamed on human emissions because the increase cannot be explained by natural causes. Although natural factors such as changes in the sun and large volcanic eruptions are known to have warmed and cooled the planet in the past, these effects are not powerful enough to explain the rapid warming seen recently. Only an increased greenhouse effect caused by higher amounts of heat-trapping gases in the atmosphere can explain it.
What is the main greenhouse gas?
Surprisingly for many, water vapour in the atmosphere produces the strongest greenhouse effect, but it has been in balance for millions of years. Human emissions have tipped that balance, think of it as being the last straw. Carbon dioxide is the chief greenhouse gas produced by human activity. It is produced when we burn the fossil fuels: oil, gas and coal and the carbon dioxide locked in them is released. The level of carbon dioxide in the atmosphere is measured in parts per million (ppm). Before the industrial revolution, the carbon dioxide level was about 280ppm; we know this because of ice core analysis. It is now 386ppm and rising by 2-3ppm each year. When other greenhouse gases such as methane are included, the total level in the atmosphere, known as the carbon dioxide equivalent, is closer to 440ppm.
What future temperature rise is expected?
Scientists say continued emissions will cause the planet to heat up further. To work out how much, they use computer models based on the programs used to predict the weather. These models are certainly not perfect. The more we know the more we realise that we have a lot to learn, but running different models and taking an average of the results, the predictions are that with emissions increase at the present rate, average temperatures will most likely increase by 4C by 2100. There are uncertainties, though - for example, the planet's oceans, forests and soils, such as the permafrost tundra could release their massive stocks of methane as the world warms, leading to much greater temperature rises than human emissions alone..
Why are warmer temperatures bad?
Most plants and animals live in a narrow ecological niche. Some are able to adapt or move to find their desired conditions, those that cannot will perish. Some animals, such as the penguin and polar bear, will have nowhere to move to. A warmer climate will affect agriculture and water availability. Increased temperatures are also expected to limit rainfall in some regions and bring more extreme weather events such as storms to others. Sea levels will rise - gradually at first as the extra warmth works its way into the oceans and makes them expand; more quickly if the gigantic ice sheets in Greenland and west Antarctica start to break up.
How can we tackle Global Warming?
It takes time for the heat to build up in the atmosphere, carbon dioxide stays in the atmosphere for a long time and so there is a lag in the system, which means the effect of any changes will not be felt for decades. Put bluntly, we are headed for about another 0.5C of warming whatever we do. The global warming supertanker is, at present, still running on. Scientists say the only realistic way at present is to reduce greenhouse gas emissions. How to do that - and where - is a political hot potato as this will involve unpopular government action and just how unpopular will be shown at the successor to the Kyoto Protocol, The Copenhagen Climate change talks.
So what are the Kyoto protocol and the Copenhagen climate talks?
The world's only existing treaty to limit emissions, the Kyoto protocol, had very limited success, and expires in 2012. Politicians are working to develop a replacement that would include countries excluded from Kyoto, such as China, and those that refused to join, such as the US. The Kyoto agreement was continually watered down and was eventually known as ‘Kyoto Light’. From December 7, environment ministers and officials will meet in Copenhagen to agree out a successor to Kyoto. This two week event is the crucial opportunity to create an international agreement on meaningful cuts in emissions that will prevent the worst consequences of climate change. This event is the world wake up call.
Can renewable energy help?
Yes! We already have the vast majority of the technology we need to bring down emissions significantly. These include renewable energy sources such as windmills, geothermal and solar panels, as well as more efficient cars and power stations.
What about carbon trading?
The idea of Carbon Trading is that a country or a group of countries (i.e. the EU) agree a maximum emissions level and companies are then given, or must purchase Carbon Credits. If a company does not use their Carbon Credit to the full, by cutting down on their pollution, they can sell the unused Credits on the open market. This may sound good, but in the EU the number of permits issued was so high that the resale value was minimal and so there was no incentive for business to cut down on pollution.
What about carbon offsetting?
I regard this as an excuse not to change our behaviour. The idea that you can pollute by flying then remove the effect of the high level pollution by paying someone to plant a tree is Alice in Wonderland environmentalism! In addition this is, in the main, an unregulated market.
What about storing the CO2 underground or blocking the sun?
One technology that would allow us to continue burning fossil fuels such as coal and oil without increasing CO2 levels in the atmosphere is carbon capture and storage (CCS). This involves extracting CO2 at power stations then pumping it underground. OK, this sounds good, but does not, at yet, exist other than in small scale testing situations, although to listen to UK government ministers you may assume that it is already in place. A more drastic approach is so-called geo-engineering. These are major technological fixes such as seeding clouds to bounce some of the sun's radiation back into space or stimulating the growth of algae in the oceans to soak up CO2. These are much more speculative, but John Holdren, Barack Obama's scientific adviser, is contemplating them.
What do the real experts say?
The leading UK scientists are at the Met Office, and you can find their Climate Change information HERE, the Climate Projection page will show you what your children/grandchildren will inherit from this generation. The leading US scientists are at NASA and you can find their information HERE, and while you look at the NASA site, run you curser over the 'Vital signs of the planet'at the top of the home page.
What can I do about it?
Act locally, think globally. Turn off lights when you are not in the room and use energy saving bulbs. Turn off standby appliances, insulate, buy local produce from local providers and local shops. If you are in the UK do you really need green beans from Kenya in January or strawberries from Egypt in March?
If at all possible, grow your own food, cut down on car mileage, cut down on plastic packaging, avoid ready meals and the associated manufacture, packaging, storage and transport environmental costs. Recycle, Repair, Reuse, and Respect God's amazing creation, because when He first made it, it was good.
Just those few items above will make a huge difference to the environment, both local and worldwide, to your pocket, and to your health.
PS. The next post will be about the multinational companies that finance climate change denial groups, misinformation adverts and greenwash...