Friday, 4 August 2017

Drawdown - review

My beloved has given me a copy of 'Drawdown - the most comprehensive plan ever proposed to reverse global warming, edited by Paul Hawken'. It is a superb book in many ways - incredibly ambitious and a real eye opener.

The book ranks 80 wide ranging strategies in terms of potential carbon savings, with estimates for up front costs and overall financial savings to 2050. Strategies range from wind power to vegetarian diets, from district heating to educating girls. There were some in the agriculture section I had never heard of such as silvipasture (growing trees and grass together for animals and tree products) and improved rice cultivation (a combination of improved planting schemes and intermittent drainage).

Some of the rankings are surprising - but on a closer inspection this is often due to their method of accounting, whereby only carbon savings over the business as usual scenario are included. This increases ranking for strategies that are not currently widespread, which is a good way to bring them to our attention.



Are you surprised by the #1 strategy: managing refrigerant gases?
Everyone seems to be surprised by the top strategy for carbon savings: refrigerant management. Globally there are tonnes of refrigerant gases in use in domestic and commercial fridges, freezers, air conditioning systems and factories; most of these have very high global warming potential so it is important to fix leaks and to collect the gases when equipment is retired. Needless to say this does not always happen. In 2014 it is estimated more than 1 million tonnes of refrigerant escaped and since these gases are thousands of times worse than carbon dioxide in global warming impact this is equivalent to several gigatons of carbon a year. Looked at this way, it is easy to see how Drawdown estimates potential carbon savings of 90 gigatons by 2050.

The text is a bit vague on this but as far as I can tell it assumes that when equipment is retired all the gas leaks unless it is specifically recovered. I imagine this is probably accurate, at least in the long term.

Most strategies save money too, but not managing refrigerant gases.
Unfortunately as well as being the best for potential carbon savings this strategy comes second worst for overall costs. In Drawdown methodology most strategies actually save money in the long term, the exceptions being refrigerant management (#1), wave and tidal power (#29), and composting (#60). There are also 20 strategies for which savings have not been calculated, usually because there are too many unknown factors.

Composting also has a net cost.
I was surprised about composting - after all it costs me nothing to make compost at home. Delving into the details (for which you need to go to their website www.drawdown.org) I see that they have compared the cost of building and operating a composting site with that of landfill. Composting costs more than landfill (if you ignore landfill tax) and the final product has a low market price even though it is high value in terms of replacing conventional fertiliser.

The EU is already strict about managing organic waste but other places are not.
The potential carbon savings for composting are also rather high, from a European perspective. This is because EU regulations require that organic material is treated before landfill to reduce methane emissions so the emissions are already being managed. However, in other parts of the world it is OK to bury the waste as it comes. Drawdown takes a global perspective. A different Drawdown strategy is to collect the methane from landfill sites and use it as a fuel (#58). This practice is also already widespread in the developed world and contributes 0.11% of global electricity production. Drawdown's 'plausible' scenario more than doubles this.

Insulation is ranked low because the business as usual scenario already does a lot.
Apart from those three, all the scenarios are projected to save money, so why aren't we doing them already? In practice we already are, to varying degrees. For example I was surprised that insulating buildings (#31) did not come higher in the ranking but that is because we are already doing quite a lot of it. In the Drawdown reference scenario we insulate 1.4 % of buildings per year, so we would get to more than 40% by 2050. The plausible scenario increases this by a third. The total carbon savings including the reference scenario would put insulation up to #10. For LED lighting on the other hand, (#44) Drawdown has estimated that the current market penetration as just 3% for commercial use and 2% for household use. They expect this to increase to at least 82% for commercial and 90% for household. So there is huge untapped potential.

Insulation has high savings because only material costs are included.
Insulation was also surprising in terms of its financial savings which seemed to me very high. Looking into their methodology they seem to have considered only material costs, excluding labour; from a global perspective labour costs may be low but from a UK perspective they are very high! This is another area where the Drawdown broad brush approach glosses over large regional differences.

Land use and agricultural strategies rank high because there is huge untapped potential.
In the media, and in my personal speciality, there is a lot of focus on energy but Drawdown rightly brings land use and agricultural issues to our attention. There are four land use strategies ranked in the top twenty. The highest is tropical forests (#5) - restoring forest areas that are partly or wholly degraded either by logging or cleared for agriculture. Restoring just a third of the potential area amounts to a huge amount of carbon storage in new forest growth. The next highest ranking land use strategy focusses on peatlands (#13); this time rather than storing carbon from the atmosphere the approach is to prevent carbon release by protecting the existing land. Dried peat is valuable as a growing medium for horticulture and when peatlands are drained the land is fertile for agriculture, but dry peat releases a huge amount of carbon into the atmosphere. Carbon stored in soil is also the focus of strategies in the food section including silvipasture (#9), regenerative agriculture (#11), tree intercropping (#17) and managed grazing (#19).


Educating girls and family planning together would be #1.
Drawdown brings our attention to the issue of global population, which is something of an elephant in the room that most commentators steer clear of for fear of giving offence. Drawdown has taken a sensitive approach including two strategies in this area: educating girls, which surely ought to be uncontroversial, and family planning, which is almost ubiquitous in the developed world even though some religions are against it. These two are ranked equal at #6 because in practice they are inextricably linked and their carbon savings have been calculated together and split equally. Considered together, they would be ranked #1.

A fascinating, browsable book with lessons for everyone.
There are many more ideas in this book that deserve to be explored. In fact the book itself is a bit of a teaser - the descriptions of each strategy are no more than 3 pages long and most of the explanations on accounting methods are online on the website. You really need to use both.

My only other quibble with the book is that the ranking table should have page numbers for each item. As it is you have to keep flicking back to the contents to find the pages. (Maybe there is a silver lining in that it gets you sidetracked into other sections and browse more widely.)

Overall this book is fascinating and enlightening. You do have to remember it takes a global perspective and its findings might need adjusting for where you live. There are lessons for everyone from policy makers, to farmers, architects and engineers, and individuals. (Meat eaters take note: a plant based diet comes in at #4.) It does a great job of bringing our attention to strategies that are less well known but have high potential.




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