CLIMATE CHANGE and GLOBAL WARMING
What is CLIMATE CHANGE?
Since the Earth formed it has been in a state of constant change. From violent beginnings it has become a cool temperature planet with an atmosphere, oceans of water, a thin crust and a hot molten core. The core is mostly iron. Inside the earth the core itself is spinning which produces a magnetic field and the North and South Magnetic Poles.
The earth spins once every 24 hours giving night and day. It spins on a tilted axis which, as the earth revolves around the sun, gives the seasons.
The warmest area of the globe is around the equator where the sun’s rays are most concentrated. The coolest area is at the poles where the sun’s rays are the weakest. This sets up a global system of warm air rising at the equator then falling again when it meets the cold air of the poles and cools down. A similar heat exchange system occurs in the oceans, affected by the position of the Earth’s land masses, causing the ocean currents. The currents affect the movement of air and therefore the weather.
When you consider that the Earth’s magnetic field, the Sun, the tilt of the Earth and the position of the land masses on the Earth’s surface are all in a constant state of movement and change, it will be no surprise that the Earth’s climate is also in a constant state of change. This change tends to be very slow but is characterized by occasional periods of very fast change, with massive and pervasive effects, such as Ice Ages or GLOBAL WARMING.
What is the “GREENHOUSE EFFECT”?
The sun’s radiation covers a wide spectrum. When it hits an object, such as the Earth, it heats the object. This heat is radiated as infrared heat. (You may recall seeing infrared pictures used to detect heat signatures of various objects or for night vision.). Much of this infrared heat radiated by the Earth escapes into space. Some of the heat is “captured” by gasses in the Earth’s atmosphere. These gasses absorb the Earths heat and re-radiate it back to the Earth. This is a good thing as it maintains a temperature range ideal to support life.
Over the life of the Earth the composition of the atmosphere varies and fluctuates in the content and concentration of various gasses. Some gasses absorb and re-radiate heat better than others so the Earth’s average temperature fluctuates with the concentration of these gasses. Despite the fact that a greenhouse operates on slightly different principles this atmospheric phenomena has come to be known as the “Greenhouse Effect”
What is GLOBAL WARMING?
One of the strongest ‘greenhouse’ gasses is Carbon Dioxide or CO2. There are many natural sources of CO2 and fluctuations of this gas have been conclusively and directly co-related to the Earth’s average temperature.
Daily records of atmospheric CO2 have been taken in Hawaii since the early 1950’s. Recent studies of atmospheric CO2 trapped in Arctic ice have extended the record back many thousands of years.
What the record shows is that each year, like the Earth taking a breath, the CO2 levels rise and fall from a peak to a trough. This has to do with the seasons and the fact that most of the Earth’s land mass and, therefore, vegetation, is in the northern hemisphere.
What it also shows is a clear and dramatic rise in the overall level of CO2 after the Industrial Revolution. From this time the levels begin to rise higher and faster until the last decade where the rise has become enormous and alarming. The so called “hockey stick” curve.
Matching the steady rise of CO2 has been a rise in average global temperature to around 0.6 of 1 degree Celsius.
Along with this rise we have seen the emergence of extreme weather events around the globe. The hottest temperatures ever recorded, the biggest storms ever seen, severe droughts, fresh water lakes and rivers drying up, extensive and unusual flooding and snowfalls, acidification of the oceans. Most starkly and alarmingly the rapid loss of ‘permanent’ ice. Ice caps melting, glaciers disappearing and permafrost thawing around the world.
Many of the predictions of the effects of global warming by the overwhelming majority of the world’s scientific community have been exceeded in size and speed.
There is a great danger that these effects will trigger massive and irreversible effects in the earth’s equilibrium which will make our planet a much more hostile and dangerous place to live.
It is clear that a major cause of this massive and exponential rise in the levels of CO2 is us.
Our contribution to CO2 levels have occurred by burning much of the earth’s stored carbon such as the fossil fuels of coal and oil. Also in the clearance and burning of the earth’s forests.
We are seriously threatening our planet on several fronts including over-population, pollution and the over use of fresh water but the most urgent problem, of all our urgent problems, is global warming. This is because we are on the brink of tipping the earth into a sequence of massive and devastating climate change over which we will have no control.
At the moment it is not too late to reduce the CO2 levels to a safer level, even though we have already caused some permanent changes.
It is up to us to take personal responsibility for ensuring our own behaviour causes minimal damage to the environment on a personal, workplace, community and global level.
If the outcome of all this will be a greater understanding and appreciation of the Earth and her finite resources and our role in the greater scheme of things then our efforts are well worth it.
"I am only one, but still I am one. I cannot do everything, but still I can do something. I will not refuse to do the something I can do."
- Helen Keller
