Gardeners, farmers, conservationists and planners should watch this recent segment produced by ABC’s ‘Catalyst’ show on how climate change is affecting the health of our harvests.

Rising CO2 levels will mean:

*Rising levels of toxic phenols, and reduced protein levels in Eucalypt leaves – goodbye koalas;
*Reduced levels of protein in cereal and grain crops, including wheat;
*Rising levels of cyanide, and reduced carbohydrate levels in cassava;

As a student at the Royal Botanic Gardens, Kew, I was taught how carbon dioxide enrichment of glasshouse crops wasn’t necessarily all good. Back then in the late 1970’s the British Ministry of Agriculture Fisheries & Food had discovered that wheat stems grown in an environment with more CO2 were weaker. Trials by thatchers using wheat stems for cottage roof thatching confirmed this. They found that industrially grown wheat thatch rotted faster than organically grown wheat thatch, but both rotted faster on roofs than traditional rush thatch.

Even in the 1980’s, when the practice of carbon enrichment of glasshouse crops in the UK started to fade out, it was known that crops grown this way were less nutritious.

I recently filmed a segment on growing cassava for Gardening Australia. In that I mentioned there are ‘sweet rooted’ cultivars which contain less cyanide, and ‘bitter rooted’ cultivars which contain more cyanide.

Gardening Australia segments produced in 2010 are getting shorter. Since rising CO2 levels increase cyanide concentrations but reduce the nutritional value of cassava, if I had been given one extra minute on air I could have suggested that home gardeners should grow ‘sweet rooted’ cassava. They are the more sustainable choice. Sadly, fewer words mean less information.

Have a look at this very important Catalyst segment, it’s an excellent report packed with useful information.

You can read the transcript here 

Jerry Coleby-Williams
9th May 2010