Climate Change Debate – Scientific Evidence part 2
Previously at www.peakfood.co.uk we have abbreviated three of The Royal Society’s responses to arguments people use to challenge man-made climate change.
Below are two further responses.
What people argue:
“Carbon dioxide only makes up a small part of the atmosphere and so cannot be responsible for global warming.”
What the science says
Carbon dioxide only makes up a small amount of the atmosphere but even in tiny concentrations it has a large influence on our climate.
The properties of greenhouse gases such as carbon dioxide mean that they strongly absorb heat-a fact that can easily be demonstrated in a simple laboratory experiment. While there are larger concentrations of other gases in the atmosphere, such as nitrogen, because they do not have these heat trapping qualities they have no effect on warming the climate whatsoever.
Water vapour is the most significant greenhouse gas. It occurs naturally although global warming caused by human activity will indirectly affect how much is in the atmosphere through, for example, increased evaporation from oceans and rivers. This will, in turn, cause either cooling or warming depending on what form the water vapour occurs in, such as different types of clouds or increased humidity.
Humans have been adding to the effect of water vapour and other naturally occurring greenhouse gases by pumping greenhouse gases such as carbon dioxide into the atmosphere through, for example, the burning of fossil fuels and deforestation. Before industrialisation carbon dioxide made up about 280 parts per million of the atmosphere. Today, due to human influence it is about 385ppm. Even these tiny amounts have resulted in an increase in global temperatures of 0.74c.
What people argue:
“Rises in the levels of carbon dioxide in the atmosphere are the result of increased temperatures, not the other way round.”
What the science says
It is true that the fluctuations in temperatures that caused the ice ages were initiated by changes in the Earth’s orbit around the Sun which, in turn, drove changes in levels of carbon dioxide in the atmosphere. This is backed up by data from the ice cores which show that rises in temperature came first, and then were followed by rises in levels of carbon dioxide up to several hundred years later. The reasons for this, although not yet fully understood, are partly because the oceans emit carbon dioxide as they heat up and absorb it when they cool down and also because soil releases greenhouse gases as it warms up. These increased levels of greenhouse gases in the atmosphere then further enhance warming, creating a ‘positive feedback’.
In contrast to this natural process, we know that the recent steep increase in the level of carbon dioxide-some 30% in the last 100 years- is not the result of natural factors. This is because, by chemical analysis, we can tell that the majority of this carbon dioxide has come from the burning of fossil fuels. And, as set out in ‘misleading argument 1’, carbon dioxide from human sources is almost certainly responsible for most of the warming over the last 50 years. There is much evidence that backs up this explanation and none that conflicts with it.
Quitting our Addiction to Economic Growth
The recent change from years of continuous economic growth though most of the world to much slower growth in Asia and negative growth in America and Europe has shown just how addicted we’ve become to continuous growth. It seems that without growth our economies cannot cope. Unemployment rises, assets fall in value and bankruptcies rise. Governments see that the boom that began by excessive debt and the illusion that property prices have made us rich without working for it has ended, so they use government debt and money creation to attempt to stimulate growth.
This apparent inability to manage without growth throws up significant problems. Economic growth increases living standards and richer people consume more of the Earth’s resources, especially fossil fuels. Indeed, it is only due to the availability of this energy collected from the sun millions of years ago that we have lifestyles undreamt of 100 years ago. Unfortunately these fuels are finite, the main reserves of oil and gas are in unstable, unreliable or unfriendly countries and their continued burning is causing the climate to change in a way that threatens our future food supply.
Does that mean that there are just two very unpalatable choices? Should we resume rapid fossil-fueled economic growth, consuming more and more of the Earth’s resources and emitting more and more greenhouse gases until the inevitable time, perhaps not far away, when we reach a rapid decline in oil and gas availability, at the same time as we experience weather related food shortages? Farming is now so dependent on finite energy inputs that food supply will in any case fail when these fuels become scarce. The panic, hoarding and breakdown of the economic system as well as law and order, that will take place when this happens will make the present recession seem like heaven.
The second option doesn’t look much better. This would be to drastically reduce our consumption of energy, thereby slowing the depletion of oil and gas reserves at the same time as reducing greenhouse gas emissions. The snag with this, of course, is that economic growth would stop, the recession would turn in to a longterm depression and the billions in the developing world would continue in abject poverty.
Looking at these two options, it appears as if we are leaving the next generation with no hope. However there is in fact a third way foreword that would be possible if the world’s leaders accept that we are facing disaster.
That third way is to use ingenuity, innovation and invention to collect far more of the abundant solar energy reaching us each day using solar panels, wind, wave and tidal collectors but most of all the age old method of collection by the plant leaf using photosynthesis.
Because fossil fuels have been so cheap and plentiful, there has been no incentive to improve the inefficient and wasteful farming methods that have become nothing more than a way to convert finite but cheap, fossil energy in the form of nitrogen fertilizer, pesticides and diesel fuel, into a much smaller amount of more expensive food energy. How can anyone think that this will not fail in the long run?
A large proportion of the energy in crops is wasted, either in the field, during processing, in the home or by feeding it to animals. There are now ways to efficiently harvest more of the crop and turn the previously wasted portion in to liquid fuels or gas. Besides traditional crops, there are developments to turn cellulose from any organic such as managed woodland or grasses, into ethanol fuel. Similarly oil can be produced from algae grown on the water that covers 70% of the planet.
If we also use technology to make it possible for us to enjoy a satisfactory lifestyle while using less total energy, we would be able to delay the depletion of fossil fuels and also reduce climatic change. What a result that would be!
The only way to make this happen quick enough to avoid disaster is to drastically change the price relationship between fossil energy and renewable energy through the tax system. We could replace income and other taxes by a carbon tax on all fossil fuels, or introduce a carbon tax with a 100% dividend. That would mean all the proceeds of the tax would be distributed back to the population.
These changes would bring about vast new industries producing both the renewable energy and the new low energy appliances, buildings and transport methods. Economic growth would no longer be leading us to disaster. It’s a possible solution.
Comment on What’s Peak Food?…
Comment on What’s Peak Food? by New Holland Hydrogen Powered Tractor | Peak Food http://ff.im/-g4Oz4
New Holland Hydrogen Powered Tractor
We have said many times that when finite oil supplies become scarce we will reach a situation of Peak Food because our farming system is now totally dependent on these fossil reserves.
So it’s good to see that at least one major tractor maker is looking to make a tractor that does not run on oil based fuel.
The NH2 tractor is a working prototype with fuel cells that generate 106 horse power. Hydrogen, stored at 350bar in a tank under the bonnet, is passed over one electrode, while oxygen (from an air pump) is passed over the other. The electricity produced by the process then passes to a pair of electric motors, one supplying drive and the other providing power for pto and auxiliary services. Because it runs on hydrogen and oxygen, the tractor’s only by-product is water.
There are at least two problems:
- Fuel cells are prohibitively expensive, though New Holland hope that commercially viable cells could come on line as soon as 2018!
- Hydrogen is really an energy storage means and needs an energy source. The conversion of energy into hydrogen, the transportation and storage of the hydrogen and its conversion back into electricity by fuel cells is very inefficient but New Holland has a vision of an energy independent farm that generates electricity on the farm using wind, solar or biogas, and then using an electrolyser to produce hydrogen which is stored in a high pressure tank.
Plainly, developing the tractor and setting up the infrastructure is not going to be a quick solution and may never be viable. However, we must give New Holland full marks for recognising that fossil powered farming can only be temporary and attempting to come up with an alternative.
Climate Change Debate – the Scientific Evidence
The severity and speed of man-made climate change is one of the key factors which will determine the amount of food that can be produced in the future. Most of us desperately wish it wasn’t happening and perhaps that explains why people are quick to believe anything coming from the sceptics. The East Anglia email scandal is an example of something fairly insignificant that is used to feed scepticism in the population, most of whom have not looked closely at the evidence or science.
I have heard people say that they would like to see the arguments explained by experts in an easy to understand way.
It’s great therefore that The Royal Society – as the UK’s national academy of science – has responded to eight key misleading arguments by setting out where the weight of scientific evidence lies.
We at Peak Food will show abbreviated versions of each of these arguments.
MISLEADING ARGUMENT 1
The Earth’s climate is always changing and this is nothing to do with humans. Even before the industrial revolution, when humans began pumping carbon dioxide into the atmosphere on a large scale, the earth experienced warmer periods.
WHAT DOES THE SCIENCE SAY?
The world has experienced warmer or colder periods in the past without any interference from humans. The ice ages are well-known examples of global changes to the climate. There have also been regional changes such as periods known as the ‘Medieval Warm Period’, when less sea ice and larger areas of cultivated land were reported in Iceland.
However, in contrast to these climate phases, the increase of three-quarters of a degree centigrade in average global temperatures over the last century is larger than can be accounted for by natural factors alone.
The Earth’s climate is complex and influenced by many things- particularly changes in the Earth’s orbit in relation to the Sun, which has driven the cycle of ice ages in the past. Volcanic eruptions and variations in the energy being emitted from the Sun have also had an effect. But even taking these factors into account, we cannot explain the temperature rises that we have seen over the last 100 years both on land and in the oceans- for example ,eleven of the last twelve years from 1995, have been the hottest years since records started in 1850.
So what is causing this increase in average global temperature? The natural greenhouse effect keeps the Earth around 30c warmer than it would otherwise be and, without it, the Earth would be extremely cold.
The ability of carbon dioxide and other greenhouse gases to act like a blanket and
trap heat has been understood for nearly 200 years and is regarded as firmly established science.
Any increase in the levels of greenhouse gases in the atmosphere mean that more heat is trapped and global temperatures increase-an effect known as ‘global warming’. We know from looking at gases found trapped in cores of polar ice that the levels of carbon dioxide in the atmosphere are now 35% greater than they have been for at least the last 650,000 years. The increase in global temperature is consistent with what science tells us we should expect when the levels of carbon dioxide and other greenhouse gases in the atmosphere increase in the way that they have.
It is alleged that the increased level of carbon dioxide in the atmosphere is due to emissions from volcanoes, but these account for less than one per cent of the emissions due to human activities.
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