The carbon cost of achieving low carbon lifestyles | Brussels Blog

The carbon cost of achieving low carbon lifestyles

posted by on 5th Aug 2015

The transition to low carbon, “modern” lifestyles
may break existing carbon budgets.

Carbon Brief reports: the remaining carbon budget to give a 66% chance of keeping global warming below 1.5°C is 243 billion tonnes. That means, if humanity emits another 243 billion tonnes of CO2e, global temperatures will rise to 1.5°C above pre-industrial levels. Using the same calculations, the remaining carbon budget, to keep below 2°C is 843 billion tonnes.

An earlier piece, “Is Green Growth a Fantasy?“, explained how this was converted to personal carbon budgets:

“World population was estimated recently at 7,317,801,293 by Worldometers. Dividing the remaining carbon budgets by the world’s population gives 33 tonnes of CO2e for a 1.5°C rise. For a 2°C rise this calculates as 115 tonnes per person.”

Is Green Growth a Fantasy? also made the assumption that this budget should last until it is possible to extract carbon dioxide from the atmosphere on a mass scale. It assumed this could start in 2050. Relying on carbon extraction maybe risky, but, according to the IPCC (and now others), there is little choice.

The report, Zero Carbon Britain,  (ZCB) from the Centre for Alternative Technology (CAT) examines carbon reduction targets to avoid dangerous climate change

“Zero Carbon Britain (ZCB) scenario demonstrates that we could rapidly reduce UK greenhouse gas (GHG) emissions to net zero by 2030, using only currently available technology.”

“We can do this whilst maintaining a modern standard of living.”

ZCB envisages some changes to lifestyles: Less travelling, a changed diet but at the same time maintaining “a modern standard of living”.

The embodied carbon in low carbon infrastructure

One problem avoided by ZCB is the embodied carbon in the infrastructure. e.g. The carbon cost of building homes, electric cars and electricity generation that makes low carbon living “a modern standard of living”.

More efficient buildings: e.g. The PassivHaus

ZCB advocates PassivHaus standard buildings because they “have very low heating demand – around 10% of an average existing building today”. However, the PassivHaus standard says little about embodied carbon. It does not count the carbon emitted in building: It focuses on carbon emitted once building is complete.

Bob Hill has applied the RICS Methodology to calculate embodied carbon of materials to estimate the embodied carbon in a normal 3 bedroomed semi-detached house of brick and block cavity wall construction. His result gives the embodied carbon for the house alone as 47 tonnes CO2e.

It is possible to build with lower embodied carbon: The RICS have calculated the embodied carbon for a sample PassivHaus design. They found it had embodied carbon of just over 20 tonnes of CO2e. However, since the authors worked “to reduce the embodied carbon of the project”, this may be idealised and perhaps difficult to achieve in practice.

Site-works and wastage

The RICS calculation did not include the embodied carbon in a garage, half the road in front of the house, the drains and other services. In Bob Hill’s example, the embodied carbon for these were 30 tonnes CO2e. Additionally, he allowed 15 tonnes of CO2e for site set-up and wastage, both together give an additional embodied carbon of 45 tonnes – giving a total of 92 tonnes CO2e for a three bed roomed house.

Electric Cars

ZCB says that most transport can be switched to very efficient electric vehicles, although some road vehicles, as well as ships and aeroplanes, will continue to need liquid fuels.

However, a report by Climate Central, Roadmap to Climate-Friendly Cars: 2013, gives carbon emissions from the manufacture of an electric car as 12.3 tonnes CO2e. Two new electric cars to be bought before 2050. That’s embodied carbon equal to 25 tonnes CO2e. (Note: the embodied carbon in s gasoline car is given as 7.4 tonnes CO2e.)

Solar panels

In What is the energy and carbon payback time for PV panels in the UK?, CAT report that the embodied energy in 1 m2 of solar panel is 250kWh of electricity. Total energy consumption in England and Wales would require solar panels with embodied carbon of about 12 tonnes CO2e per person.

A rough estimate of the embodied carbon getting to the “modern standard of living”

A rough estimate of the embodied carbon getting to the “modern standard of living”.

We have Bob Hills house (47 tonnes CO2e), for site-works and wastage (45 tonnes), electric cars (25 tonnes), Solar Panels (12 tonnes). For (more efficient) household appliances and other considerations like shops, offices and schools add 30% (30 tonnes). This gives 168  tonnes CO2e for the average sized household or 70 tonnes CO2e per person compared to personal carbon budgets of 33 tonnes CO2e for 1.5degC or 115 tonnes CO2e for 2degC.

Current construction methods using bricks, concrete and steel to build cities for a  “modern standard of living” cause embodied carbon emissions which are a large proportion of the personal carbon budgets, leaving very little for everyday living. This would be of less consequence if cities expanded slowly in the coming decades: New city dwellers might exceeding their remaining carbon budget but they might count on others to stay below.

However,  in World Urbanisation Prospects, the United Nations say  “The continuing urbanization and overall growth of the world’s population is projected to add 2.5 billion people to the urban population by 2050”. That could be a problem!

The problem gets worse if the IPCC’s remaining carbon budgets are over estimates. There are strong grounds for believing this is the case because the CMIP5 Earth Systems models, that they used to calculate these budgets had missing feedbacks, such as the increase in forest fires.  Updated models would almost certainly give reduced budgets.

Over time, as new urban areas are constructed, it will be possible to reduce the embodied carbon – as with the example of the PassivHaus above – but time is of the essence.  If the IPCCs reliance on extracting carbon dioxide from the atmosphere is taken seriously – if it isn’t, there is real disaster, – then the global remaining budget must be eked out, until say 2060: 70 tonnes of CO2e from a budget of  115 tonnes leaves less than 45 tonnes CO2e. The carbon footprint per person in the UK is about 20 tonnes CO2e per year.

Missing feedbacks probably make this much worse.


Low carbon production: How soon?

With a low carbon lifestyle in place, low carbon electricity can be used to make solar panels, electric cars & etc: They will then have lower embodied carbon. But can low carbon production be achieved soon enough without exceeding the remaining carbon budgets? This is not a question ZCB attempts.

The calculation of embodied carbon suggests that the target lifestyles of Zero Carbon Britain be incompatible with saving the climate.



New report for the European Commission

A new report funded by the European Commission by the New Climate Institute, Impacts of good practice policies on regional and global greenhouse gas emissions, envisages a continuation and expansion of “modern” lifestyles

“Good practice policies can decrease the energy and carbon intensity to levels required for 2°C in the analysed sectors, while maintaining or even increasing the activities. An increase in activity may especially occur in developing countries, for example as an increase of access to electricity, vehicle ownership, increase use of electric appliances, larger floor space of housing facilities, etc.”

The report does not mention the carbon emissions necessary to build the infrastructure for “access to electricity, vehicle ownership, increase use of electric appliances, larger floor space of housing facilities”.

In the section “Further research” the report also says

“The study assumes that the good practice policies can be implemented without significant delays globally. However, policy implementation is very complex and dependent on country specific circumstances.”

The embodied carbon in creating low carbon but “modern” lifestyles should be added to their “further research” list.


POSTSCRIPT 2nd November 2015:

Solar Panels are now more efficient

On Neven’s Arctic Forum, SteveMDFP has pointed to recently published What’s the EROI of Solar? This shows that solar panels are now considerably more efficient than quoted in CAT’s  What is the energy and carbon payback time for PV panels in the UK? This relies on a study published by the US Department of Energy in 2004.

The embodied CO2e for that solar panel scenario will now be less than 12 tonnes for each person.



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