Climate Change update Part 2

April 23, 2015

Why are they called ‘fossil’ fuels?

Around 165 million years ago, vast numbers of little animals and plants called plankton lived in the world’s oceans. They are still living in the oceans today. But lots and lots of plankton that were living in the oceans all those millions of years ago died and sank to the bottom of the ocean. They were covered over with silt, crushed by immense forces and over the course of millions of years, they turned into the thick black sludgy stuff buried under our planet’s surface that we call crude oil. So oil is a kind of black gloopy fossil.

The same kind of thing happened in huge forests covering the land millions of years ago. The trees died, fell, were covered over and turned over millions of years into the black burnable rocks we know as coal. Natural gas was formed when layers of dead plants and animals were exposed to intense pressure and heat over millions of years. It can also be formed more quickly deep down in marshes, bogs and even landfill sites!

So why is it a problem that we’re burning all these old plants and animals from millions of years ago? Well, all living things contain quite a lot of a substance called carbon. Plants, while they are alive absorb a gas called carbon dioxide (CO2), which they combine with sunlight and water to create starch, which provides the energy for them to live and grow. When they die and rot away, they release the carbon contained in themselves slowly and naturally back into the atmosphere. This process is called the carbon cycle.

Each year, animals and microbes (really small life forms) between them emit about 220 billion tonnes of CO2 into the atmosphere. Plants emit CO2 at night when they can’t photosynthesise, and this adds about another 220 billion tonnes to the atmosphere each year. But those plants absorb about 440 billion tonnes of carbon dioxide through photosynthesis each year, so this is all balanced out. Parts of the oceans will be emitting CO2 (around 330 billion tonnes per year), but this is balanced out by other parts of the oceans, which will absorb about 330 billion tonnes of CO2 each year. So in nature, the balance of gases in the planet’s atmosphere remains similar from year to year.

The carbon contained in fossil fuels was buried before it could be released back into the atmosphere, so it has been locked away for millions of years. By burning fossil fuels, we are releasing that carbon back into the atmosphere in the form of carbon dioxide. So we are adding huge amounts (about 32.3 billion tonnes in 2014) of extra carbon dioxide into the atmosphere each year. About 40% of this extra carbon dioxide can still be absorbed by nature via the carbon cycle, but the other 60% ends up in the atmosphere, and that is upsetting the planet’s ability to maintain a steady level of carbon dioxide in the atmosphere. In fact, carbon dioxide levels remained at between 180 and 300 parts per million in the Earth’s atmosphere for the last 500,000 years. But in the last couple of centuries, the level of carbon dioxide has increased to 380 parts per million.

Carbon dioxide and the greenhouse effect

‘So’, you may think, ‘there’s more carbon dioxide in the atmosphere. We can’t see it, we can’t smell it, why’s that a problem?’. Well, it is a problem because carbon dioxide is a ‘greenhouse gas’ As it builds up in the atmosphere, it helps to trap more and more of the heat energy that the sun fires at our planet every day, a bit like wrapping the Earth in a blanket, or building a greenhouse around it. So as we make the blanket thicker, we increase the amount of heat that is held in our planet’s atmosphere, and gradually the planet gets hotter. You can find a video about how the greenhouse effect works here https://ypte.org.uk/videos/the-greenhouse-effect.

Carbon dioxide isn’t the only greenhouse gas, others include methane, nitrous oxide, ozone and water vapour. Carbon dioxide is the second most abundant greenhouse gas in the atmosphere - water vapour is the biggest component. The trouble is that the planet gets warmer because we increase the amount of carbon dioxide in the atmosphere by burning more fossil fuels. The increased heat means that more water evaporates from the oceans, so there is more water vapour in the atmosphere, which means the greenhouse effect gets stronger, which means the planet gets warmer, which means there is more water vapour in the atmosphere, and so on…

Since 1900, the planet has warmed up by about 0.8 degrees Centigrade, but by 2100, the temperature increase could be a further 2-5 degrees Centigrade. The last time the planet warmed by 5 degrees, it took 5,000 years and brought us out of the Ice Age. If left unstopped, we could create the same amount of warming in about 100 years!

Could climate change be a good thing?

While almost all scientists agree that climate change is definitely happening and that this is a bad thing not only for humans, but for the animal and plant life with which we share the planet, some think that climate change might not be such a bad thing. One example is Professor Richard Tol of Sussex University. His 2009 study on the effects of climate change found that viewed planet-wide, it would actually be a good thing until about 2080.

The benefits are small and have been felt more by rich countries than poor ones. It seems pretty much certain that after 2080, climate change would have negative impacts, but until then, the positives include less human deaths in winter - cold winters kill far more people than summer heat waves do, either in the UK or even Greece!

Meanwhile, increased levels of atmospheric carbon dioxide have actually been good for plants. A study of satellite data from the last 30 years by Dr Ranga Myengi of Boston University has found that 31% of areas covered in vegetation have become greener, while only 3% have become less green. This means that a 14% increase in the productivity of vegetation has been seen across a range of global ecosystems.

So climate change could actually be a good thing, at least for another 60 years, according to some scientists. They are currently very much in the minority. This does not necessarily mean that they are wrong. However, even they agree that after 2080, unchecked climate change will definitely be a bad thing. The big challenge for humanity is that the climate is a bit like a fire that you might light in your fireplace (if you have one) at home. The fire gets going and it’s nice and cosy. To keep the fire going, you throw on more logs now and then and maybe it starts to get too hot. When you stop adding logs, the fire doesn’t immediately stop burning and while it’s still burning the room is still hot and for a while might still be getting hotter. The world’s climate is like that fireplace, but on a much bigger scale. Even if we cut our emissions of greenhouse gases right now, today, it would be decades before the planet stopped warming up, which is why tackling climate change is an urgent problem for us all now.

Why climate change is probably a bad thing

Climate change is such an important issue that the United Nations has assembled a huge panel of thousands of climate experts from around the world. The Intergovernmental Panel on Climate Change (IPCC) provides the world’s governments with predictions on what will happen and what needs to be done now to prevent climate change causing catastrophic problems for our planet in the future. The latest IPCC Report, published in 2014, provides almost total agreement that humans are causing climate change.

The Report states that our actions are warming the oceans and atmosphere, sea levels are rising as snow cover melts along with Arctic sea ice, which will threaten coastal areas and low-lying communities and cities. As oceans absorb more and more carbon dioxide from the atmosphere, they are becoming more acidic, which will cause loss of coral and big changes for many marine species. Extreme weather like storms, heavy rainfall, droughts and heat waves are very likely to increase. Unless action is taken, we may not be able to grow enough food to feed everyone and a lack of water in some areas may cause mass migration and even wars.

Even with action, because the world’s fireplace is already burning, we will still need to adapt to some of the changes to climate that are already unavoidable.

While extreme weather seems to be in the news all the time, a study by independent scholar Indur Goklany has found that in fact the number of human deaths from floods, droughts and storms has dropped by 98% since the 1920s. He argues that this is not because the weather events are any less dangerous, it’s because we are much better at forecasting, giving people time to get out of the way before the bad weather hits and because we are investing more as a species in better protection against storms, floods and droughts. As countries become steadily richer, he believes protection against extreme weather will continue to improve too.

Those adaptations are being seen by some as an opportunity to make the world a more robust and secure place for our future. As Dr Chris Field said “If we’re dumb, it’s a serious, serious problem and if we are smart it’s a serious problem, but one that we can manage”.

Photo of dying corals by Silke Baron

In the next article: The problem is already here and what we can do to help.

If you want to read the whole of Conservation Education now, you can download it here:

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