Doing The Math: our global carbon budget

Have you heard of our ‘global carbon budget’?  It’s the maximum amount of oil, coal and natural gas humanity can still burn if we wish to limit global warming to two degrees C.

(Two degrees C is considered the maximum safe limit for global warming.  Our past consumption of fossil fuels has already warmed the planet about one degree C – and with all the recent worldwide heatwaves and wildfires, one could be forgiven for believing that even that’s already too much warming.)

Our global carbon budget declines a little every day for every tonne of coal, every litre of oil and every cubic metre of natural gas that we consume.

So how much can we still burn?  How long will that take, at today’s levels of consumption?  Or maybe we’ll deplete our fossil fuel reserves before that happens?

It all sounds complicated – but it’s made crystal clear in this powerful and concise video by Bill McKibben, author, academic and founder of  It’s essential watching for anyone who wishes to understand one of the most daunting challenges we face in addressing climate change.  (I’ve started using the video in my presentations because it explains the issue far better than I can.)

If you don’t have time for the full six minutes, fast-forward to the 1:45 mark and start from there; you’ll still get the gist of the issue.  And once you do, why not share the video among your network?

Dry cleaning’s dirty little secret

Dry cleaning is widely accepted as being the best – or even only – way to clean our most delicate fabrics.  But it’s surprising what you find when you dig a little deeper.

Traditional dry cleaning isn’t really ‘dry’: dirt and stains are removed by a liquid solvent called perchloroethylene, or perc for short.  And perc has some unsavoury characteristics:

  • It’s very volatile (meaning it evaporates easily), and is listed as a toxic substance under the Canadian Environmental Protection Act. According to the US EPA, it causes a myriad of health effects ranging from respiratory tract irritation to dizziness to cancer.  That’s a potential hazard for dry cleaning employees, but it also means that any residual perc in clothes you’ve had dry cleaned will come out in your airspace.
  • When spilled, even small amounts of perc can contaminate huge amounts of groundwater for a long time.

There are greener alternatives to perc, but they aren’t common practice yet: it’s estimated that over three quarters of dry cleaning is still done with perc.

So what to do?

  • When buying, look for clothes that don’t require dry cleaning (you’ll save on cleaning costs too)
  • When a garment label says ‘dry clean only’, do you really need to dry clean? This Chatelaine article sheds some light.
  • For clothes that absolutely must be dry cleaned, stretch the interval as long as you dare
  • Ask your dry cleaner what process they use, and inquire about greener alternatives like wet cleaning and liquid carbon dioxide cleaning; a nice overview of both processes here.

Amazing what a difference you can make with wise clothing choices – and avoiding conventional dry cleaning is one of them!