Carbon dioxide in the atmosphere matters

Sunlight reaching our planet is dominantly a short-wavelength energy, which passes easily through our atmosphere to warm the surface of the planet. As the surface warms, it emits an increasing amount of infrared, or long-wavelength, energy back out into the atmosphere: the incoming short-wavelength energy has been converted into outgoing long-wavelength energy.

Molecules made up of two atoms of the same element, such as nitrogen (N2) or oxygen (O2), have no net change in their dipole moment when they vibrate and so do not absorb infrared energy, but 3-atom (or more) molecules, such as carbon dioxide (CO2), do. Consequently nitrogen and oxygen are not greenhouse gases as the infrared energy emitted from the planet surface would easily pass back out through an atmosphere of these gases.

By contrast, carbon dioxide does absorb the outgoing infrared energy, gradually accumulating more heat and increasing the temperature of the planet’s surface. The greater the concentration of carbon dioxide, the more the temperature increases.

It is well-known that the greenhouse effect of the carbon dioxide currently in our atmosphere is about 33°C. In other words, the planet surface is about 33°C warmer than it would be without the greenhouse effect. As it stands, this is enormously beneficial to us, for a planet 33°C cooler than now would not be habitable by humans.

However, the converse is also true. A planet substantially warmer than now would not be habitable by humans either. Consequently, fundamental questions for us as a species are whether our activity is actually capable of increasing the carbon dioxide concentration significantly and how much any such increase is liable to increase the temperature.

Global carbon emissions to double

The recently published Global Emissions Trends analysis projects that in a "business as usual" scenario (i.e. no changes to carbon emission policies) global carbon emissions will double by 2030.

This would make the IPCC target of a 50% reduction in global carbon emissions by 2050 (on 1990 levels) difficult to achieve, increasing the probability of global mean temperatures rising above the critical level of +2 Degrees. (See why 2 Degrees is a critical level in The 2 Degree Target).

Under this scenario:

• Developing countries will account for 70 per cent of global carbon dioxide by 2030, up from around half today, with China (41%) and India (11%) taking the largest share, due to increasing population (+22% by 2030), industrialisation, and the greater energy demands as living standards improve in these countries.
  
• Australia's carbon emissions would rise 24% by 2020. The strong growth in emissions would be dominated by the extraction and processing of energy resources.
  

This disastrous scenario will not happen if governments shape public policy to transition towards a low-carbon future. This research forms part of eight papers in the Garnaut Climate Change Review - Update 2011.

Five Degrees difference changes our landscape

It is estimated that the increasing levels of carbon dioxide in the atmosphere will almost certainly lead to a 2 Degree rise in global temperatures. It has been suggested that because the consequences of a 2 Degree rise are already certain, it would be better to invest in preparing for the consequences of more extreme weather events and rising sea levels rather than reducing emissions.

However, if mankind does not change it’s appetite for fossil fuels then average temperatures will rise by more than 2 Degrees. As Bill McKibben of 350.org said, there are different degrees of hell. The consequences of a 3 Degree rise are much more severe than 2 Degrees, and 4 Degrees is even worse.

For those who say that the world has survived greater variations in average temperature, they are right. Over the last 5 billion years temperatures have been more extreme and the world has kept turning. But is has a devastating impact on mankind and all biodiversity.

The last time the global average temperatures were 5 Degrees different from today was during the last ice age, when temperatures were much cooler. As a result, New York was under 15 meters of ice. The impact of a similar rise in global average temperatures would be different but just as catastrophic.

The big carbon footprint in food

Everything has a carbon footprint. But when most of us think of our carbon footprint we think in terms of the carbon emissions from energy, such as electricity or transport. Few people would consider the large contribution to the household carbon footprint of food. However, a recent study by Taverner Research (commissioned by Willoughby Council on Willoughby residents), looked at the holistic carbon footprint per household and found that almost half the emissions, 47% on average, are a result of the food we buy.

The study shows that a household of three people is responsible for 38.7 tonnes of carbon emissions per annum on average, with food being the largest contributor (47%), then travel (27%), Household Energy - including electricity, gas, heating and cooling (24%) and Waste (2%). Table 1 shows the household carbon emissions per activity in tonnes of CO2e.

Table 1: Carbon Emissions per household activity

Interestingly, but not unexpected, the research showed that carbon emissions per occupant decreases as the number of people living in the household increases. Because occupants share some energy consumption and therefore each occupant is responsible for fewer carbon emissions. The study found that an individual on their own is responsible for 14.9 tonnes of carbon emissions on average, which is much higher than the average carbon emissions per individual across all research participants of 11.97 tonnes.

Carbon emissions are almost one-third lower per occupant in a household of five people compared to a household with a sole occupant.


This research clearly shows we need to consider more than just the energy we use when considering our impact on the environment. While there is merit in cohabitation in order to reduce the carbon emissions per occupant, the real opportunities to reduce our carbon footprint appear to be found in what we eat. A big part of an individual’s carbon footprint comes from food. Our next article looks at ways to reduce your carbon footprint from food.

Effective Carbon Offsets are an Answer to Climate Change

The Australian Government has delayed the implementation of an Australian Emissions Trading Scheme (ETS) until 2013. This failure at the political level has severely retarded the ability of Australia as a nation to effectively combat climate change. With no framework to regulate the reduction of carbon emissions in Australia, the onus is now on individuals and organisations to voluntarily reduce emissions in order to help drive the transition to a low-carbon future.

So how does an organisation or individual most effectively reduce global carbon emissions? Certainly, the need to avoid and reduce energy use is necessary and financially beneficial, but more is needed to achieve the deep cuts in carbon emissions required to reduce damaging climate change.

We need to reduce the amount of carbon mankind emits to the atmosphere. One way to achieve this is through effective carbon offsets.

Carbon offsetting allows you to reduce carbon emissions by a cheaper and more convenient process elsewhere than you can achieve yourself.

Forestry and renewables have been common offset solutions. About half of Australia’s offsets are created through forestry; the rest is mostly renewables with some greenhouse gas trapping projects (mostly methane).

However, many of these schemes deal with the symptom and not the cause - they do not directly promote the reduction of carbon emitted by industry. They are reactive. Worse still, the lack of an ETS in Australia has serious implications for the use of Australian projects as voluntary carbon offsets for Australians, as they may not be additional.

A more effective carbon offset, which is measurable, verifiable and additional, is the internationally recognised carbon emission credit from a carbon market such as the European ETS. Paul Gilding, ex-CEO of Greenpeace International, referred to buying and voluntarily cancelling the rights of industry to emit carbon dioxide from a limited pool of carbon emission credits as the ‘most pure’ form of carbon offset.

Do international offsets have a positive effect on countries who do not have a carbon market? Yes, because climate change is a global problem. Reducing carbon emissions anywhere in the world will help save the future as we know it for the entire world.

What makes a tonne of carbon emissions?

To help you understand how your everyday activities add to the changing climate we have created a table showing what makes a tonne of carbon emissions.

Each of these activities results in 1 tonne of carbon emissions on average.

• Travelling in a plane for 5000 kms / 3100 miles (about 3.5 return trips Sydney/Melbourne; 3 return trips New York/Chicago; 11 trips London/Paris)*
  
• Driving a car with petrol/[US gas] about 4100 kms / 2500 miles
  
• Using a clothes dryer for 15 hours
  
• Turning on 10 light globes (100 Watts) for 68 days
  
• Using a window air conditioner for 75 days
  
• Staying 34 nights in a hotel

* for more detail on the carbon emissions from flying visit Travel Math

If you have any examples of an activity that results in approximately 1 tonne of carbon emissions please add it in a comment!

Are Deep Cuts In Carbon Emissions Optional?

Most people consider sustainable initiatives a necessity, but some believe that carbon offsetting is optional. It is important to consider why carbon offsetting is any more optional than the sustainable initiatives to measure, avoid and reduce carbon emissions. If the answer is the cost to offset carbon and the Return-On-Investment, then the time has come to change our way of thinking.

The current scientific evidence on climate change indicates there is a drastically urgent need to make deep cuts in carbon emissions immediately.

Reducing energy consumption alone will not achieve enough. For as we reduce energy consumption, the energy we save is being consumed by an increase in consumer demand and an increase in global population.

The real solution is to encourage industry to invest in alternative low-carbon solutions. This requires an increase in the price of carbon so that low-carbon solutions such as renewable energy appear economically attractive.

Reducing carbon emission credits in a carbon market can achieve this goal, because it helps speed up the transition to a low-carbon future. Climakind gives organisations access to cancel carbon emission credits (CECs) and works with them to ensure their efforts to the right thing and help stop damaging climate change are recognised. Find out how at http://www.climakind.com/.

Image credits flikr missallphoto's