It has been four years since I wrote The A-Z of Global Warming, so I thought about time to produce a revised and updated version. CO2 levels have continued to rise and global warming headlines still dominate the news in one form or another. In fact a new term has been coined – global weirding, which describes the world’s increasingly odd and erratic weather patterns. I have updated the chapters with the latest relevant information on the subject and added hyperlinks to source material and news items. If you have read this book before, you will hopefully get a clear picture of what has been going on over the last four years. If it is your first read, all the better, as you get the 2008 position and updated picture. At the end of each chapter, new material can be found under the heading, 2012: Update.
With that in mind, let’s begin The A-Z of Global Warming…
It’s not possible to get through the day without hearing something about global warming or climate change on the news, or reading about the subject in the papers. Indeed to most people, including myself before writing this book, the issues seemed so complex, confusing and contradictory, that it was hard to know exactly what was really going on: whether the world really was warming up, whether the situation was being exaggerated or whether the causes of global warming, if occurring, were manmade or not. It is now clear that something is indeed going on with Earth’s climate. Polar ice caps appear to be melting, or at least the pictures on the news seem to show this to be the case. There is constant mention of rising carbon dioxide levels, and there always appear to be high-powered meetings going on between nations to discuss the climate. One only recently took place in Bali in December where climate change and global warming were hotly (excuse the pun) discussed.
Following a viewing in the cinema in November 2006 of Al Gore’s documentary An Inconvenient Truth, I felt inspired to research, read about and find out as much as I could on the subject of climate change and global warming. I bought numerous books, scanned the internet and trawled through enormous amounts of information written on the subject, from multiple sources, in order to gain as comprehensive an understanding as I could on the issues of global warming. Information for this book came from organisations such as the National Aeronautics and Space Administration (NASA), The National Oceanic Atmospheric Administration (NOAA), the Stern Review on The Economics of Climate Change, The World Wildlife Fund (WWF), and Mongabay, to name a few. After a while I conceived the idea of an A–Z on the subject, which would make it quick and easy for anyone who wanted a good knowledge of global warming with a book that got straight to the heart of this very complex topic. All the related issues of global warming and climate change have been packed into A–Z format, with each chapter dealing with a specific point on the subject. I have used the term ‘global warming’ as in my view it most accurately describes what is in fact happening to planet Earth on a global scale. However, as a result of global warming, there will of course be climatic change in different parts of the world, whether it be higher temperatures, rainfall, drought or hurricanes, or even perhaps localised cooling.
Global warming: A brief introduction
The term ‘global warming’ has been in common usage for some time and usually refers to recent warming of Earth’s atmosphere, which also implies a manmade or human influence. Each chapter of this book deals with an aspect of it, but as an introduction, here is a quick overview. Earth’s atmosphere comprises many gases: oxygen, nitrogen, carbon dioxide (hereafter abbreviated to CO2) and water vapour, to name a few. These gases are collectively called greenhouse gases and they keep the Earth’s temperature at a comfortable 15°C. Without them Earth would be a chilly -18°C. Since pre-industrial times, usually taken to be before 1750, we know from ice-core records that CO2 levels were about 280 ppm, that’s 280 parts of CO2 per million parts of air. As industrialisation got underway humankind started to farm the land more intensely than ever before, which included deforestation for agriculture and settlements. Later – since about 1850 or so – the burning of fossil fuels for energy and transport has added considerably to greenhouse gas levels, particularly CO2. This has resulted in CO2 levels increasing to about 385 ppm, a rise of about thirty-seven per cent from pre-industrial levels – mainly as a result of burning fossil fuels. How do we know this? Well, data from ice-core records that go back at least 650,000 years now show us that CO2 levels have fluctuated naturally during this time between 280 and 300 ppm. CO2 levels have also been measured accurately from the top of Mauna Loa Volcano in Hawaii since 1958, and results show an increase in CO2 levels from 315 ppm to 380 ppm since that time. Therefore CO2 is now at eighty ppm more than it has been for at least 650,000 years of Earth’s history. It is a known scientific fact that higher levels of greenhouse gases will lead to higher temperatures, which appears to be happening now. The world has warmed by an average of 0.74 degrees Celsius during the last 100 years or so. As a result of this warming, polar ice has started to decrease and melt, and so have Earth’s land-based glaciers. This in turn is causing sea levels to rise, which is putting low-lying islands at risk of flooding or total submersion, and will eventually threaten more and more of the world’s coastal cities and regions. Things may get worse, however, because once Earth’s atmosphere starts to warm, the warming itself may cause further positive feedback mechanisms to kick in. A warmer atmosphere holds more water vapour, which is itself a powerful greenhouse gas. This will in turn cause further warming, and so on. Melting ice results in more sunlight absorbed by the surrounding ‘darker’ water and land, and that results in further warming, and more melting ice. Methane deposits currently held in a frozen but stable state under the sea and under the permafrost may be released as the oceans warm and permafrost melts, which will cause further warming as methane is a potent greenhouse gas etc., etc.
That is global warming in a nutshell, but is humankind really to blame? Read this book, and make up your own mind. I hope to explain everything in an uncomplicated way, and will look at all the issues in much more detail, starting with the involvement of the Amazon rainforest, biofuels, CO2 and so on, with each chapter having relevance to the phenomenon of global warming. Earth’s historical climate is looked at, the sun’s role, the Kyoto Agreement is explained, and the findings of the Intergovernmental Panel on Climate Change (IPCC), a unique panel comprising many thousands of researchers and scientists from all over the world, are revealed. Towards the end of the book, the consequences of global warming are looked at in terms of the weather, diseases, extinction, and importantly what the world and every human being on it can do to try and alleviate the crisis that planet Earth and all of us are facing. I hope from reading this book you will learn something and perhaps get concerned enough to do something about the problem…
A – AMAZON
We start our A–Z journey on global warming with the Amazon rainforest, which has an incredibly important role to play in maintaining balance in the Earth’s climate, in ways that are only just being understood. The Amazon is inextricably linked to the issue of global warming and therefore a very good place to start our inquiry into what may be the biggest threat to our existence on this planet.
The Amazon river basin contains the largest rainforest on Earth and covers approximately forty per cent of the South American continent. The rainforest is located in eight countries. Brazil has sixty per cent, with Colombia, Peru, Venezuela, Ecuador, Bolivia, Guyana, Suriname and French Guyana between them containing the rest. The Amazon forest is a natural reservoir of genetic diversity, containing the largest and most species-rich tract of tropical rainforest that exists. The Amazon contains an amazing thirty per cent of Earth’s species. One square kilometre can sustain about 90,000 tons of living plants! It’s also amazing to consider that one in five of all the birds in the world make the rainforest their home. The Amazon basin is drained by the Amazon River, the world’s second longest after the Nile. The river is essentially the lifeline of the forest. It is the most voluminous on Earth and its daily freshwater discharge into the Atlantic is enough to supply New York City’s freshwater needs for nine years!1 New measurements recently taken by scientists, however, suggest that the Amazon may actually be the longest river in the world. No doubt this will be confirmed if true, at some point in the future!
A few thousand years ago tropical rainforests covered as much as twelve per cent of the Earth’s land surface, but today the figure is below five per cent. The largest stretch of rainforest can be found in the Amazon river basin, over half of which is situated in Brazil.2
Why is the Amazon so important in the context of global warming?
The rainforest acts as a major store of carbon and produces enormous amounts of oxygen. The Amazon has been referred to as ‘the lungs of the Earth’ because of its affect on the climate. The way this is achieved is of course through photosynthesis, the process by which green plants and trees use the energy from sunlight to produce food by taking CO2 from the air and water and converting it to carbon. The by-product of this is oxygen. The Amazon therefore helps recycle CO2 by turning it into oxygen, and it is estimated that the Amazon produces about twenty per cent of this essential gas for Earth’s atmosphere.
Trees, plants and CO2
Levels of CO2 in the atmosphere have been measured since 1958, from a monitoring station located on Mauna Loa volcano in Hawaii. They show sharp annual increases and decreases in CO2 levels, similar to the tooth on a saw. The readings seem to mimic a breath of air being taken in and out, almost as if the Earth is breathing. They correspond to the amount of vegetation on the
planet (most of which is in the northern hemisphere, as the landmass there is greater), taking in CO2, and giving out oxygen. During summer in the northern hemisphere, when the Earth is tilted towards the sun, Earth’s vegetation is able to photosynthesise, resulting in an uptake of CO2, causing worldwide CO2 levels to drop. In winter in the northern hemisphere, when Earth’s axis is tilted away from the sun, the opposite happens, causing CO2 levels to rise again.
When one becomes aware of the correlation between the Earth’s vegetation and CO2 levels, it is easy to understand why the Amazon, and rainforests in general, are such an important part of Earth’s ecosystem. The problem is, however, that although the measurements taken at the volcano in Hawaii show sharp up and down annual readings, the measurements also show a simultaneous steady upward trend in CO2 levels. The importance of CO2 in relation to global warming will be a recurring theme throughout this book, and will be looked at further in Chapter C.
What has been happening in the Amazon?
A worrying trend is the Amazon having experienced two consecutive years of drought, in 2005 and 2006. The drought in 2005, which left rivers dry, stranded thousands of villagers, and put regional commerce at a standstill, was the worst on record. A second year of drought is of great concern to researchers studying the Amazon ecosystem. Field studies by the Massachusetts-based Woods Hole Research Centre in the USA, suggest that Amazon forest ecosystems may not withstand more than two consecutive years of drought without starting to break down. Severe drought weakens forest trees and dries leaf litter leaving forests susceptible to land-clearing fires set during the July-October period each year. According to the Woods Hole Research Centre, it also puts forest ecosystems at risk of shifting into a savannah-like state.3
A recent experiment carried out by a team of researchers suspended 5,600 large plastic panels between 1 and 4 metres (3.2– 13.1 feet) above the ground to mimic severe drought conditions, where as much as eighty per cent of a one-hectare plot is deprived of eighty per cent of rainfall. Measuring rainfall, soil moisture, leaf and canopy characteristics over time, it was found that after
four years the rainforest trees began to die while leaf litter dried and became tinder for wild fires.4
Another factor is the El Niño Southern Oscillation (ENSO) event, a climatic phenomenon that influences much of the climate in the region, particularly Northeast Brazil, and the northern Amazon. ENSO brings with it dry conditions in the above areas, and manmade climate change is thought to increase this naturally occurring phenomenon in the future. ENSO is further looked at
in Chapter W.
Some climate models have suggested that temperatures in the Amazon may increase by 2 to 3°C (3.6–5.4°F) by the year 2050, together with a decrease in rainfall during the dry period. If the drought continues, based on the results of the aforementioned experiment, 2007/8 could be a turning point for the forest, which may mean that a tipping point will be reached where the forest will start to die, with catastrophic consequences for Earth’s climate.
If this trend continues, according to the WWF, between thirty and sixty per cent of the Amazon rainforest could become dry savannah, rendering the forest a source of CO2 instead of a sink/ store of it, which it currently is. There are ways in which we can all help try and sustain this vast and ecologically important expanse of rainforest, and these will be discussed in Chapter Y.
The Amazon will be considered further in Chapter D, where the problem of deforestation is looked at.
We will now consider the importance of biofuels as an alternative source of fuel, and how biofuels may help in the fight against global warming. Ironically, this is also causing problems for the Amazon and other rainforests, as areas of forest are cleared for the planting of crops for biofuel production.
So, what’s been happening in the Amazon over the last four years? The “one-in-100” year drought that struck the Amazon in 2005 returned in 2010, this time possibly releasing into the atmosphere more than the 5 billion tons of carbon dioxide than the 2005 drought did. Experts fear that if such extreme droughts become more frequent – which appears to be the case – the Amazon may cease to provide a natural buffer to man-made carbon emissions.
Dr Simon Lewis, from the University of Leeds reported in the Journal of Science, “Having two events of this magnitude in such close succession is extremely unusual, but unfortunately consistent with those climate models that project a grim future for Amazonia.” – Mongabay.
Global climate simulations suggest that further droughts, such as the ones in 2005 and 2010 could eventually turn the Amazon from a carbon sink to a carbon emitter. Researches now fear that the apparent increase of severe droughts – caused by a combination of climate change, fragmentation and deforestation – could cause the collapse of the Amazon rainforest ecosystem. The UK’s Guardian newspaper covered the story in some detail, read it, here and here.
A new study on its way to being published shows that the Amazon rainforest suffered greatly from last year’s drought. Employing satellite data and supercomputing technology, researchers have found that the Amazon was likely hit harder by 2010’s drought than a recent severe drought from 2005. The droughts have supported predictions by the Intergovernmental Panel on Climate Change’s (IPCC) that climate change, among other impacts, could push portions of the Amazon to grasslands, devastating the world’s greatest rainforest. “The greenness levels of Amazonian vegetation—a measure of its health—decreased dramatically over an area more than three and one-half times the size of Texas and did not recover to normal levels, even after the drought ended in late October 2010,” explains the study’s lead author Liang Xu of Boston University – Mongabay.
According to Mongabay, scientists, using climate simulation models at the UK’s Hadley Center for Climate Prediction and Research, have forecast significant “die-back” of the Amazon rainforest by mid-century and a virtual collapse of the ecosystem by 2100. So, it would seem that if the current trend continues, the future of Earth’s largest rainforest looks bleak.
Click on the following photograph from the National Geographic website, taken in November 2010, which shows the Negro River, a tributary of the Amazon coming to an abrupt end.
The Amazon is further looked at in chapter D in terms of deforestation.
➢ The Amazon rainforest contains about thirty per cent of Earth’s species.
➢ World rainforest cover has over thousands of years decreased from twelve per cent to five per cent.
➢ The Amazon helps to recycle CO2, a gas which contributes to global warming and while doing so produces about twenty per cent of Earth’s oxygen.
➢ CO2 levels rise and fall with the seasons. There is greater landmass and hence vegetation in the northern hemisphere, which means that when Earth is tilted towards the sun during northern summertime, CO2 levels drop as a result of there being greater uptake of CO2 from photosynthesis. During the winter, the opposite happens and CO2 levels rise again.
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Next blog, find out about The A-Z of Global Warming, letter B and Biofuels – Thanks for reading.