Welcome to a regular new column dedicated to Climate Change written by Phil Shotton, the Ramsgate Society Lead on Environment and Climate Change. Each column will look at the science, the data, what it all means and what we can do about it.
Expect straightforward explanations, myth-busting, and practical advice, all based on the facts, not rumour, hearsay or conspiracy theories. As an introduction, let’s introduce climate change, and what it means.
Climate Change refers to the effects on the earth’s climate caused by human activities. The old name, Global Warming, is less used now, not because the world isn’t getting warmer (it is), but because the climate effects of warming are many and varied. For some regions, and at some times during the year, the climate may actually be cooler. What is certain and obvious from events over the last few years, is that climatic events are becoming more extreme, with higher highs, lower lows, stronger winds, and both wetter and drier periods.
Climatic events, at their most basic, are driven by energy. The more energy available, the larger the event. As the planet warms, the energy driving our weather increases, and so the weather becomes more extreme.
The evidence overwhelmingly points to a warmer world being caused primarily by increased amounts of greenhouse gases in our environment.
Greenhouse gases are so named because their presence in the atmosphere retains solar energy (heat) like a greenhouse, preventing it from leaking away into space. Without some level of these gases the world would be very cold, but increasing levels cause global temperatures to rise. There are many greenhouse gases, the most abundant and well known being carbon dioxide and methane, but with others such as many refrigerant gases also significant.
Carbon dioxide (CO2) has been a climate influencer for millions of years. The last ice age ended largely because of the release of CO2 from the earth’s crust as a result of volcanic activity. The levels of CO2 now in the atmosphere are hugely more than in the last many thousands of years, and most result from human activities since the beginning of the industrial revolution.
Scientists have been measuring atmospheric CO2 directly for many decades, but historic levels can also be determined from ice cores drilled in deep ice in the arctic and antarctic.
The following graph shows CO2 levels over the last 800 thousand years. Note that CO2 has gone up and down on a regular cycle, but in the past 60+ years the level has increased to nearly double the largest levels over the last millenia.