Sunny Intervals

The 'greenhouse effect' is a misnomer, or a somewhat weak metaphor. Greenhose glass let in the sun's radiation, which heats the air, soil and anything else that is inside. The glass is a physical barrier against the movement of air, so convection - which would normally dissipate the heat into the wider atmosphere - is restricted, keeping the heat confined within the glass walls. Higher temperature means faster plant growth, means higher yields and earlier harvests

For businesses, markets and seasonal prices determine which crops are worth growing under glass and which are not. As globalisation of markets has developed, the economics of what is and is not worth the high cost of production under glass has changed. It's not uncommon to see empty commercial greenhouses becoming derelict in UK, their viability undermined by imports that can be produced more cheaply. The cost of living versus food security; who would be a politician

Plastic greenhouses ('polytunnels') exploit the same physics but are cheaper to build and maintain. Now you can add into the policy choices the generation of plastic waste and pollution, the embedded energy in plastic versus that in glass, visual amenity and health & safety

The planetary greenhouse effect is a phenomenon in which the surface of the earth absorbs heat from the sun's rays, then re-emits it at a different wavelength. The changing composition of the atmosphere means that more and more of the re-emitted heat is absorbed by it, rather than escaping back into space. Like a greenhouse on a sunny day, where no-one has painted the glass to limit the incoming heat, or opened the windows and doors to let it out, the inside is getting hotter and hotter, and anything inside is at risk of destruction. Perhaps it's not a bad metaphor after all

The PV panels are absorbing the sun's energy to generate power without adding more greenhouse gasses to the atmosphere. The organic crops are producing food with as little fossil fuel input as possible - and also converting the sun's energy into something we need, of course

I took the picture because I like the long, (nearly) straight lines and a bed devoted to each crop. Now I realise there is a bigger story