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16 November 2012

PwC Low Carbon Economy Index: your comments

This year’s PwC Low Carbon Economy Index (LCEI) has generated plenty of comments and questions.  Here's a selection of them.

From Christiana Figueres “Ahead of COP18, PwC points to urgent need to raise global level of ambition to curb GHG emissions”

Using our LCEI model, we will estimate the absolute emissions targets consistent with 2 degrees C, that countries will need to agree at COP21 and implement in the 2020’s.  We will publish this in advance of COP18 in Doha. 

How did you do the numbers? 

The LCEI model is relatively simple.  For the G20 economies, we use energy data from BP’s Statistical Review and GDP data from the World Bank.  We make projections about changes in primary energy intensity, the fuel mix and GDP growth for each country.  We have made assumptions about emissions from other countries (not in the G20) and non-energy sectors (land use change etc).   We take the IPCC estimates of atmospheric stabilisation levels to meet 2, 4 and 6 degrees, and from that derive the respective global carbon budget allowed. We can then calculate the annual change in carbon intensity that is needed to stay within those carbon budgets. Although we don’t audit the underlying data from BP or the World Bank, we do check the numbers in our model.

“Is it reasonable to assume that the changes in the next 20 years will be the same as between 2080 and 2100?”

Although the report focuses on the period to 2050 (the LCEI model is based on PwC’s ‘World in 2050’ economic model), we assume constant rates of decarbonisation from now to 2100.  Our current rate of decarbonisation averages 0.8% per year.  The table on page 9 of the report shows four different decarbonisation rates, from now to 2100, and the resulting implied concentration levels.  We believe that this is simpler to communicate than a scenario analysis which might assume particular energy or economic transformations in the decades to come.

“Your comment 'Sectors dependent on food, water, energy or ecosystem services need to scrutinise the resilience and viability of their supply chain'  would seem to me to include the entire physical world...?"

Yes quite! But stating the obvious is sometimes necessary. Also some sectors will be more exposed than others, so they will be the first and hardest hit by the effects of climate change.

If you’ve other questions or comments, please tweet us @pwcclimateready.
Read the PwC Low Carbon Economy Index or watch the webcast here