Is the Scale of Climate Change overstated?

March 28, 2010 · Filed Under news · Comment 

Many people say:

“The scale of the negative effects of climate change is often overstated and there is no need for urgent action.”

What does the science – and the Royal Society – say?

Under one of its mid range estimates, the Inter Governmental Panel on Climate Change (IPCC) – the world’s leading authority on climate change – has projected a global average temperature increase this century of two to three degrees centigrade. This would mean that the earth will experience a larger climate change than it has experienced for at least 10,000 years. The impact and pace of this change would be difficult for many people and the ecosystems to adapt to.

However, the IPCC has pointed out that as climate change progresses it is likely that negative effects wold begin to dominate almost everywhere. Increasing temperatures are likely, for example to increase the frequency and severity of weather events such as heatwaves, storms and flooding.

Furthermore there are real concerns that, in the longterm, rising levels of greenhouse gases in the atmosphere could set in motion large scale and potentially abrupt changes in our planet’s natural systems and some of these could be irreversible. Increasing temperatures could, for example, lead to the melting of large ice sheets with major consequences for low lying areas throughout the world.

And the impact of climate change will fall disproportionately upon developing countries and the poor – those who could can least afford to adapt. Thus a changing climate will exacerbate inequalities in, for example, health and access to adequate food and water.

Number of Sunspots effect Earth’s Temperature?

March 24, 2010 · Filed Under news · Comment 

People want to believe climate change isn’t happening.  One common argument used used is: 

It’s all to do with the sun – for example, there is a strong link between the increased temperature on earth and the number of sunspots on the sun.

But what does the science – and the Royal Society –  say?

 Change in solar activity is one of the many factors that influence the climate but cannot, on its own, account for the change in global average temperature that we have seen in the 21st century.

 Changes in the sun’s activity influence the earth’s climate through small but significant variations in its intensity. When it is a more “active” phase – as indicated by a greater number of sunspots on its surface – it emits more light and heat. While there is evidence of a link between solar activity and some of the warming in the early 20th century, measurements from satellites show that there has been very little change in underlying solar activity in the last 30 years. There is even evidence of a detectable decline – and so this cannot account for the recent rises we have seen in global temperatures. The magnitude and pattern of changes to temperatures can only be understood by taking all of the relevant factors – both natural and human – into account. For example, major volcanic eruptions produce a cooling effect because they blast ash and other particles into the atmosphere where they persist for a few years and reduce the amount of the sun’s energy that reaches the earth’s surface. Also, burning fossil fuels produces particles called sulphate aerosols which tend to cool the climate in the same way. Over the first part of the 20th century higher levels of solar activity combined with increases in human generated carbon dioxide to raise temperatures. Between 1940 and 1970 the carbon dioxide effect was probably offset by increasing amounts of sulphate aerosols in the atmosphere, and a slight downturn in solar activity, as well as enhanced volcanic activity.

During this period global temperatures dropped. However, in the latter part of the 20th century temperatures rose well above the levels of the 1940s. Strong measures taken to reduce sulphate pollution in some regions of the world meant that industrial aerosols began to provide less compensation for an increasing warming caused by carbon dioxide. The rising temperature during this period has been partly abated by occasional volcanic eruptions.

Why Modern Farming is Unsustainable

February 21, 2010 · Filed Under security of energy supply · Comment 

The farmer’s job is to manage the original solar energy collector-the plant leaf.   We use the sun’s energy collected by plants to take the carbon from carbon dioxide and the hydrogen from water to synthesise carbohydrates and give off oxygen. When the carbohydrate is eaten, burned or it just decays, the opposite happens- oxygen is required, carbon dioxide and water are given up and energy is released.

Of course, this is nothing new. This cycle was working perfectly well long before farmers came on the scene. We merely try to improve on nature by fighting pests and disease, by providing optimum nutrition and by trying to eliminate plants from our fields other than those that we wish to harvest.

Green plants are the only primary producers of foodstuffs and humans are dependent on plants for all of their food, either directly or indirectly. All of our human energy comes from the sun and the feeding of the world depends on our ability to collect enough solar energy and convert it to food energy through farming plants .It used to be so simple. Around 30% of crops were used to fuel the horses, oxen and humans to provide the muscle for field and transport work. Soil fertility was maintained by recycling nutrients, crop rotation including nitrogen fixing legumes and fallows. Yields were low but so was the world population.

But in the past 70 years or so there has been a dramatic development that has enabled the world population to triple. WE have found a way to cheat!

Instead of just converting current sunshine in to food energy we have found how to convert ancient sunshine collected by pre-historic plants and marine organisms in to food energy.

We now convert hydrocarbons in to carbohydrates.

The present population of nearly7 billion people is being supported not just on current sunshine but on sunshine that reached this earth millions of years ago.

The land previously used to feed work animals can now be used to provide human food as diesel engines provide the muscle. Fossil fuel sourced pesticides and nitrogen fertiliser have dramatically increased yields and enabled the green revolution in India and elsewhere.

Amazingly, if transport and processing is included, we now use about 10 calories of fossil energy to produce each calorie of food energy in an average meat based diet.

Converting fossil energy in to a smaller amount of more expensive food energy worked well when fossil energy was cheap and plentiful but will fail when it is scarce and expensive.

Climate Change Debate – Scientific Evidence part 2

February 19, 2010 · Filed Under news · 2 Comments 

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.