de Baz,

This is an *extreme* over-simplification.

To obey the fundamental laws of physics; if you put energy into a system, the system heats up.

For some time now we have been releasing (exponentially) much more energy into the system at a rate greater than the system has been able to absorb.

For a very much longer time, the concentration of CO2 in a component (atmosphere) of the system hovered around 280 ppm. Today, the concentration of CO2 in the atmosphere is about 385 ppm, an increase of about 40% over pre-industrial levels (it’s the mass that matters, but we won’t go into that here). There is a vast body of research that attributes most of this increase to the burning of fossil fuels and poor resource management practices.

Measurements have shown that we are adding CO2 at a rate of about 2 ppm per year. However, where people get really confused is in their misunderstanding of the IPCC’s emission scenarios (SRES). This is the nub of Garnaut’s interim findings.

You are right (in simplified terms) that the forcing of CO2 is logarithmic (~ 5.3 log [CO2]/[ CO2_init]) and in terms of temperature, it equates to about a 60% increase in warming for a tripling of [CO2] than that of a doubling from pre-industrial levels (for example) … this is where I think you get confused.

Another problem; because oceans take a long time to warm up, there is more ‘warming’ to come (from previous CO2 emissions). So, on top of the 0.7 ºC we have already experienced since pre-industrial times, there is another 0.5 ºC in the pipe-line.

At the concentrations we are looking at, measurements and observations show the planet’s global average temperature is increasing at a rate of about 0.2 ºC per decade with ‘climate sensitivity’ at about 3 ºC for a doubling of CO2.

When you factor in forcings from the other GHG’s (and deforestation practices) into the SRES’s *business as usual* scenario, the additional warming would be about 2 to 5 ºC.

This is BIG in our scheme of things.

Bazz, start here:

http://en.wikipedia.org/wiki/Global_warming

Back to topic,

Again simplistic, but what say anyone to this?

To stabilise atmospheric CO2 at 560 ppm will require a 75% reduction of emissions from business-as-usual (currently about 8 billion tons per year) to a rate of about 2 billion tons per year.

The largest GHG emitting countries in the world emit about 75% of the global total. They can reduce global emissions by 75% if they reduce their emissions to zilch … methinks not.

OTOH, if these same countries reduce their emissions by about 60%, then all the remaining countries’ emissions would have to be zilch … methinks not.

We are told 560 ppm equates to about 2 degrees C above pre-industrial levels.

Following the above logic, the planet will have to adapt to a *warmer* world.

It would be prudent to reduce GHG emissions as much as we can – 90% seems ‘off-the-planet’.

Ok then to all of you who keep saying that we must stop the population growth.

1. How many of you have children of your own?

2. Of these how many wish for thier children to provide them with grand children?

3. If any one of you answered yes to both questions, then which side of the fence do you realy sit on?

The to the anti-progress posters.

1. Are you comfortable participating in this debate with the knowledge that progrees has allowed you to do so?

2. Would you be happy to sell your car, turn off your air-con on a 30deg+ day or walk to work provided your workplace provided 60% less lighting.

With the risk of sounding like a broken record, we must learn to deal with CO2 rather than just try to reduce it to unachievable levels.

1. No kids
2. N/A
3. N/A

1. Yes
2. Live out of town so need car. No Aircon. House designed to be cool in summer, warm in winter.

David

I am sorry to be an optimist but there is a solution and it will make us richer (which will reduce the population) and we can do it in a couple of decades.

Think of the problem as one of investment rather than one of cutting emissions. How much investment in renewables do we need to reduce our emissions to zero and then to start to take gases out of the atmosphere.

Take the total energy output (including transport, industrial processes, agriculture) of Australia, divide by the number of people, and you get between 70Kwh and 90kwh depending on whose energy numbers you start with.

If we use existing technology (solar thermal or geothermal) then it costs us about 3000 to produce about 9000 kwhs so the investment needed for each Australian is about $30K at existing technology prices. We know that large scale industrial processes improve their efficiency in the early stages of development by about 10% per year so it will probably cost about $20K over ten years or about 40 billion a year. 40 billion a year is 1/6th the amount we currently spend buying existing houses.

At the end of the time we will have zero net emissions and energy at half the current wholesale cost.

This is not a doomsday scenario it is an economic growth scenario.

Let's keep burning coal until the science on other forms of eco-friendly alternatives is more advanced, viable and cost efficient.
The Green Movement, and political parties of the Green persuasion, are often made up of former socialists and Communists.
The Green Movement , like Communistic type movements and political parties often come up with issues that are relevant but are also often short on viable solutions and often the 'solutions' are wrong in therory and practice from common sense and objective moral and economic norms.( economic norms that is that spring from objective morals, not to be confused with economic rationalism that sadly is ruining many of our industries, moving them offshore and closing them down.