Hi Nina,
Certain gases exist in the atmosphere that have the capacity to retain heat, collectively they’re known as the greenhouse gases.
Most greenhouse gases occur naturally and it’s their presence that retains enough heat to ensure our planet is habitable. If such gases weren’t there, or they didn’t trap heat, then Earth would lose it’s ‘insulation’ and it would be so cold that it would freeze solid.
Human activities produce these same gases, most notably carbon dioxide, methane and nitrous oxide. They come from industrial processes, manufacturing, power generation, the burning of fossil fuels (coal, oil, gas) and a whole host of other sources.
These gases are entering the atmosphere where they reside for a long period of time and they’re adding to the greenhouse gases that are already there. For millions of years the level of these gases in the atmosphere varied only a little, but since the world became industrialised and we started pumping out these gases, levels have dramatically increased.
Because there’s now more of the greenhouse gases there’s also more heat being trapped by them and it’s this trapping of the heat that we refer to as global warming.
As the planet warms up it starts to affect weather patterns, this is what we refer to as climate change.
The reason it’s such a big issue now is that the climate is warming far faster than any natural change could ever produce and the consequences are affecting all of us; some much more so than others.
If you compare the global weather today with that of say 50 years ago you’ll see that there’s quite noticeable differences. Not only is it somewhat warmer, but there’s been a very significant increase in the number of extreme weather events including floods, droughts and heatwaves.
As the world warms up it’s also melting the ice in the polar regions and this is running off as rivers into the seas and oceans which is causing sea-levels to rise. The amount of water that’s melting is the equivalent of ten River Nile’s emptying into the world’s oceans. At the same time, the water is expanding because it’s warming up. In recent decades sea-levels have risen by an average of 3.2mm every year, faster than at any time since the last ‘ice-age’ ended.
Rising sea-levels mean that low lying islands and coastal areas become flooded, fresh-water supplies become contaminated and coastlines erode more rapidly.
Two of the biggest problems caused by climate change are the disruptions to food and water supplies. Higher temperatures and more extreme weather and resulting in massive crop failures which is leading to famines in Africa, more now than ever before.
The warmer temperatures have melted half the world’s glaciers outside the Polar regions, many millions of people depend on meltwater from glaciers and with supplies drying up they’ve been forced to migrate elsewhere. The lack of water is also killing crops and animals and turning once fertile areas into deserts.
One of the things about climate change is that it’s progressive, the climate doesn’t suddenly change. If it did it would be much more obvious. It’s more insidious and the changes happen over many years, such that from one year to the next we don’t really notice a change.
The weather we get today we think of as being normal but if you compare it to the weather of 50 or 100 years ago then it’s quite different.
For example, it appears you’re in the UK, you’ll be only too aware that 2 and 3 winters ago the UK had heavy snowfall and very cold temperatures, it caught the whole country out and came as a shock to many people. Whilst that particular weather was unusual, if you go back to say your grandparents days then it wasn’t that unusual at all and in fact, those two ‘severe’ winters were positively tame compared to some of the winters in the 40’s, 50’s and 60’s.
Same too with UK summers. I’m not sure how old you are but ask people who were around in 1976 what the weather was like that year and they’ll tell you of the ‘long, hot summer’. Back in ’76 the conditions were exceptional and are implanted in the memories of those who were there. Since then there have been no less than 14 warmer summers but we’re now so used to them that they’re considered ‘normal’.
If you are in the UK then the biggest change in respect of climate change concerns the amount of rainfall and especially the floods it causes. There’s now three times as many floods as there were 30 years ago and by the year 2050 it’s probable there will be seven times the number.
In other parts of the UK, especially the south and the east, rainfall levels are falling. There are currently drought conditions in much of England south of the Midlands, something that’s almost unheard of at this time of year. Unless there’s very significant rainfall then there could be serious problems in the southeast this summer.