World population

I recently came across a superb lecture on global population growth by the statistician Hans Rosling "Don't panic: the facts about population". Based on the latest UN data, populations in billions are predicted to be:

	2010	2050	2100
America	1	1	1
Europe	1	1	1
Africa	1	2	4
Asia	4	5	5
Total	7	9	11

There is uncertainty in these predictions, for example back around 2000 the UN predicted global population at 9 ± 1.5 billion by 2050, although it seems unlikely that they will be fundamentally incorrect unless there is a cataclysm.

What's changed since 2009?

A lot should have happened since my last posting in 2009 so I've decided to brush up my knowledge by taking the FutureLearn course "Climate change: challenges and solutions" run by the University of Exeter

Amongst the developments that I need to consider are:

1. Global warming has apparently levelled out and no one knows why.
2. World population shows signs of stabilising at around 11 billion by 2100.
3. The economies of China and India still grow rapidly and their populations aspire to Western standards of living.
4. Financing of major new projects has been badly hit by global recession.
5. Nuclear has had its Fukushima moment yet there are still sparks amongst the embers, including in the UK.
6. Thorium cycle has been touted as an inherently safer way to exploit nuclear power.
7. Fracking is the new kid on the block, bringing revolutionary change to US energy supply and potentially also to the UK.
8. Investment in renewables has proceeded apace.

I will take stock of the progress that has been made in the nearly quarter of a century since my original study in 1990 and have decided to extend my horizon to 2100 because 2025 is only ten years away and too immediate to consider major strategic options.

University of East Anglia Climate Disaster

Arguably the greatest damage to the credibility of scientists and the future of mankind has been achieved at a single stroke by the Climatic Research Unit of the University of East Anglia. Not only have raw data on world climate been destroyed in an unparalleled act of vandalism but the 'corrected' data have been massaged to portray a less ambiguous picture of the warming of our planet.

As a result, the reputation of all scientists has been tarnished and the value of many major infrastructure projects will be called into question. Decisions on energy production will now be based on wild political assertion rather than fact and scientists presenting the risks and benefits of competing energy systems will be dismissed for manipulating the facts to their own ends.

Perhaps it's time to consider going off-grid, seeking high ground and becoming self-sufficient?

Green and pleasant UK - transport

Transport offers major opportunities for change. Teleworking is already a practical proposition. Many of us are beginning to realize that making a journey on foot or bicycle keeps us fitter and more alert. Road travel accounts for over 80% of the total energy consumed in transport. We need to change the emphasis from personal to social. Park and ride schemes have the potential to reduce fuel consumption for commuters and shoppers by perhaps 50% given appropriate investments in public transport. Improving the quality of service and tuning rail fares have the potential to attract substantial passenger and freight traffic from the roads.

Air travel accounts for only a few percent of the total energy expended on transport but receives great attention from the green lobby because it is the fastest growing component. Improving fuel efficiency, increasing load factors and switching to rail for domestic and European destinations would give us a good chance of holding current emission levels.

Overall it should be possible to achieve a 30% reduction in carbon dioxide emissions from transport

Green and pleasant UK - land use

Changes in land use have two possible effects. CO2 emissions are increased by conversion of forest and grassland to other uses such as factories and housing; CO2 removal is increased by planting of forest and abandonment of managed lands. Emissions and removals are currently about 8 MtC and 5 MtC per year respectively. Halting the conversion to other uses, e.g. by more intensive use of brownfield sites for factories and housing, and slightly more than doubling the amount of forest to about 5 million hectares shifts from net emission of 3 MtC to net removal of 10 MtC per year. This future UK is beginning to look a more green and pleasant land.

Why don't we plant sufficient forest and woodland to balance all emissions? One hectare of a maturing temperate forest removes nearly 4 tons of carbon per year, enough to offset one person's requirements for fossil fuel. Unfortunately the UK landmass is not quite 25 million hectares, less than half the area that would be required for 55 million people. On the other hand, such a strategy would be viable in North America or France where the population densities are much lower than in the UK.

Green and pleasant UK - setting a target

Kyoto was inevitably a triumph for the agility of politicians and the power of commerce over the uncertainty of scientists. So here we are, in the next millennium, gambling on the chance that global warming is a false prophesy, continuing with our current patterns of energy consumption and, as they manifest themselves, living with the consequences of sea level rise, extreme weather and climate change, mitigating them as best we can. We place ourselves at hostage to drought, flood, famine, mass migrations and all the social instabilities that these bring.

But I wonder what would be the consequences of taking deliberate steps towards stabilizing atmospheric carbon dioxide concentration at its present level, i.e. aiming for a reduction of about 60% in current global emissions? Is such a reduction technically and economically feasible? How long would it take? And what would our world look like?

Consider firstly the UK since, although it makes only a small contribution to global emissions, it epitomizes the challenge to nations with high per capita energy consumption. What if we were to reduce our annual per capita energy consumption from 3.7 tons of oil equivalent (toe) to 1.5 toe, comparable to that in Argentina and Iran? This would still be 50% more than China and nearly five times greater than India but such a reduction would most likely be associated with a significant drop in the material quality of our lives. Such a move would be unlikely to be popular and would almost certainly be politically unacceptable to most Governments.

So is it possible for the UK to maintain its current per capita energy consumption whilst reducing carbon dioxide emissions by 60%? Annual emissions (NETCEN; expressed as million tons of carbon - MtC) by sector in the UK for 1990 and 2000 are shown in the following figure, along with an indicative target total for 60% reduction from 1990 values:



How might we achieve this target?

Standard of living

The 1989 study considered countries of the North ('haves') and South ('have-nots'), corresponding closely to the 'more developed' and 'less developed' regions defined by UN Population Division. The latter terminology will be used in the current study.

There continues to be a great discrepancy in wealth between more developed and less developed countries. In 2004 the world average per capita GDP (based on purchasing power parity) is US$8,200. At the top of the table is Luxembourg with US$55,000; at the bottom East Timor with US$500. The USA weighs in at US$37,800, Japan US$28,200, EU countries US$20,000 to 30,000, China US$5,000 and India US$2,900.

World population

The principal driver for world energy consumption, as for all scarce resources, is the world population.



World population reached 6 billion in 1999. The UN predicts 9 ± 1.5 billion by 2050, with the majority of the growth occurring in the less-developed countries.

Atmospheric CO2

This is what all the fuss is about.



The facts are:

• The concentration of carbon dioxide in the atmosphere has risen steadily since the Industrial Revolution at a rate related to the burning of fossil fuels.
• Carbon dioxide is a 'greenhouse gas' that has an influence on the Earth's heat balance. All other things being equal, the higher its concentration becomes, the higher will be the Earth's temperature.

The big debate is about whether this simple relationship holds or is counter-balanced by other factors influencing the heat balance. And, if it does hold, what will be the impact of future CO2 emissions on global climate?

Setting the scene

In 1989 I helped Dr J.K. Wright prepare a lecture on The Global Impact of Nuclear Power for the European postgraduate summer school at the University of Gent. The content was subsequently published in the December 1989 edition of Atom.

The analysis examined the socio-economic and technical factors that would influence energy supply and demand out to 2025 and specifically the contribution that nuclear power might make to the limitation of carbon dioxide emissions. The conclusions in 1989 were as follows:
"The world population is increasing more rapidly than ever before. Moreover we are more conscious of the need to help raise the standard of living of the developing world than ever before. This requires a massive effort from many quarters, but the provision of an adequate supply of energy is an essential ingredient. We have seen that, with plausible conservation measures, the world is likely to need over double the existing annual supply of energy by 2025 if the standard of living of the developing world is to continue to expand at even its present rate. If we were to burn fossil fuel at the present rate and ignore the greenhouse effect consequences and if we were to develop all the practicable hydro schemes in the world, we would still only meet half the energy needs. It will be difficult enough to supply adequate energy if nuclear power is able to make a significant contribution. To abandon the nuclear option now could make the task impossible."

Fifteen years have elapsed since those conclusions were drawn. In that time nuclear power has entered the doldrums, gas has been king and evidence has grown steadily for the impact of increasing atmospheric CO2 concentration on global warming and climate change.

The time has come to revisit the analysis to determine whether our original conclusions still hold good. The analysis is based on a very simple model in which likely future needs for energy are projected from three factors:
world energy demand=
world population x GDP/person x energy/GDP
Impacts on the environment follow directly from the sources that are used to satisfy the demand. The following authoritative sources have been used. Links to these sources vary from year to year; an up to date set may be found at Thornbury 2050 - Resources:

• The World Factbook - CIA overview
• BP Statistical Reviews - historical energy data
• UN Population Division - projections to 2050
• World Bank - background to GDP