Global carbon emissions

Carbon emissions since 2004 can be prepared at the World Bank website. The following graphs illustrate total and per capita carbon emissions for a range of countries:




China has already overtaken the USA as the biggest emitter and is continuing to steadily increase emissions. The big question is whether China will be able to hold its per capita emissions at the UK level or will follow the USA. Either way it's populations and their aspiration to be as wealthy as the West which will be driving emissions.

Climate change: challenges & solutions - plumbing the depths of my ignorance

Fascinating course and well-presented although raising more questions than answers given the depth of my ignorance.

I'm still confused by our ability to use a single temperature to characterise global climate.

I'll start with the last 50 years which has used very sophisticated ground and satellite based techniques for measuring the weather. Put simply I don't understand what methods have been used for averaging over the Earth's surface. Taking an extreme case: how are temperatures in the Himalayas accommodated? Do they contribute according to the area exposed to the atmosphere because that would be most appropriate for heat transfer and sublimation? Or is the area taken simply as that on a map, i.e. projected area? And if the latter, what allowance if any is made for altitude?

And tree rings presumably provide evidence on temperature and rainfall in the growing season but what assumptions have to be made about the rest of the year?

Ice cores go back millennia and provide evidence on relatively long periods of time so what assumptions are made about the variability within those periods?

Good discussions of these matters at: UEA FAQs and on the NASA Goddard Institute for Space Studies pages. Also some explanations at the latter site about how data from ice cores, tree rings etc etc are consolidated.

Poorest countries are not most energy efficient!!

There is an interesting Wikipedia article on energy intensity which presents the following plot of individual wealth v energy efficience (return) around the year 2000 for the world's top 40 economies:

This seems to suggest that there is some sort of 'boomerang' effect in which the least wealthy (least productive) countries generate the greatest economic return on energy consumed, i.e. the poorest seem to be the most highly energy efficient. Increasing wealth seems to be related to a reducing return on energy employed until reaching those countries where individuals are at least moderately wealthy (productive) at which point increasing wealth is associated with an increasing return on energy consumed.

Rather than a real effect is it possible that the 'boomerang' is caused by some artefact of the data being analysed? Wood is omitted from most energy budgets and this can be a major source of energy in some economies. For example, consider the USA from 1790 to 2006:

Once wood is accounting for it seems that the boomerang effect disappears and the US has been steadily increasing individual wealth while improving energy effectiveness, i.e. increasing the return on energy consumed.

What about a country like Bangladesh?

It seems that once wood is included in the energy consumption Bangladesh is not quite so highly energy efficient as we might have thought. Not only that but it exhibits the same trend of increasing individual wealth with improving the return on energy consumed.

So the poorest countries do not achieve the greatest return on energy consumed; increasing individual wealth is instead associated with increasing efficiency of energy use!

A few definitions

Before analysing GDP and energy demand it is necessary to give a few definitions. The descriptions of the following terms may not be universally agreed but they are essentially those that I used in my first posting although they have been modified to emphasise the approach that I will use in my next posts. For a given region:

• Energy demand (E) =
   Population (P) x Wealth (W) x Return (R)
• Wealth is GDP/person.
• Return is the GDP returned for each unit of energy employed.

World energy demand is simply a sum over each of the world's regions as follows. In my original work in 1989 I considered two regions, North and South, which was a convenient and politically correct way to categorise the developed (rich) and developing (poor) nations of the world. Twenty five years on and it is now more useful to group nations by continent:

• America
• Europe
• Africa
• Asia

Current and predicted populations for each continent have been considered in an earlier post.

My next post will consider a misconception about the efficiency with which energy generates a return in GDP.