'morning Craig,

Thanks for such a detailed and informative explanation. Unfortunately, you seem to have missed the main point, again. Would farmers around the world prefer to deal with blight or wish to solve the problem with less rain?

I'm guessing that your case will be along the lines that if you can exaggerate blight infection to around 70% globally, you can easily discount the benefit of more rainfall?

ConservativeHippie, although Kelvin was wrong on the oxygen issue, the air pressure on a horizontal surface is, on average, the weight of the air above that surface.

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Craig, why does CO2 affect fungal growth?

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spindoc, AIUI the main problem is that global warming is predicted to make subtropical semiarid areas dryer and droughts longer.

BTW potatoes are native not to forests but to the highland grasslands of the Andes.

Hi Aidan, I don't claim to be an expert on this topic, so I can't give you a definitive answer. However, greenhouse producers who artificially add CO2 to their atmospheres have to be especially careful to control mould. I'm sure there must be good literature on the subject.

It may be that there is an enhanced opportunity for mould to enter plant tissue as a result of faster growth rates and increased humidity. Leaf stoma remain open longer, stem tissues are not as robust (less compact structure) due to faster growth, perhaps plants devote more metabolic resources to growth, thereby reducing immune responses. There may simply be more dead plant material for fungal spores to get a start in. The growth of most fungi is not directly related to CO2, although some of the pathogenic soil fungi do like high CO2. It doesn't take very long for a fungal blight to destroy a crop. Ask the Irish.Some species of phytopthera (the potato blight fungus) also infest other food crops. Leaf rusts and fungal infestations of flowers, seed pods and harvested seed are already endemic for grains.

Spindoc, the point I was making is quite simple: while the increased yields are great, at some point there is going to be a catastrophic crop collapse, whether in one year or across several. The chance of that occurring is increased by the likelihood of lazy fungal management, especially in the rotation of fungicides. I'm not sure what the farmer's feelings about that have to do with anything at all.

Greenies are such cheerful souls.

Here we have Craig Minns, who may have privately realised that CO2 is not going to cause much if any global warming, trying to invent a new scare, to blame on this poor innocent plant food. They are desperate to find something incriminating against their great hate, carbon based energy. Yep they hate coal & oil as they are the materials that set us free of their wish to subjugate & dominate us.

This effort is a bit thin however. After naively trying to use an association with CO2 used in greenhouses, with no evidence, he has to back away, hoping to have left some incrimination of CO2 behind. This hope surely being the only reason for the bit of rubbish.

He then reverts to the usual greenie impersonation of Hanrahan, with a "We'll all be rooned," type dissertation on some future repeat of the Irish potato blight, with absolutely nothing to support such an idea, except perhaps green wishful thinking.

We all know these people would love to see the human population gone, but for themselves of course, & now some of them are getting close to openly hoping for it. What lovely people. They'll shortly be flying to Paris from all over the world, somehow justifying to themselves that all that CO2 they generated getting there is good, because it is theirs. Hypocrites all.

Hasbeen, I'm no more a "greenie" than you are an engineer...

However, let's face it, your generation, thanks to witless tools like yourself who couldn't work out how to plan their way out of a wet paper bag, has buggered the planet.

Go away, old man, you're a waste of space.

‘morning Craig,

Hasbeen does have a point Craig. Rather than debate the issue with your undoubted intellect, you abuse another poster for daring to challenge yet more of your alarmist predictions, this time of a “catastrophic crop collapse”.

Trying to scare people into believing such alarmism is losing traction in the public domain. Also abuse against those who disagree is likewise costing you credibility, which is quite sad really because you do appear to have a brain however, your frustration at not getting your own way is hanging out.

It could be said that if you cannot make a case without an exaggerated catastrophic “prediction”, then quite simply you don’t have a case at all.

So if you don’t have a case, why bag out someone else for your problem?