There’s no mistaking green business is now big business. Consumer demand for environmental and ethical choice has companies queuing up to profess their green credentials – and cash in on the green pound.Essentially that’s a good thing, right? After all, who could have imagined just five years ago that Tesco would pledge £500m to reduce its carbon emissions or Marks & Spencer set targets to cut emissions by 80% and become carbon neutral inside five years at a cost of £200m?That’s really walking the talk. Shame other brands continue to just talk.Not that the consumer is falling for it. The Advertising Standards Authority revealed today complaints about ‘green’ ads considered misleading or ‘greenwashing’ more than doubled in 2007. Ads by Toyota, Ryanair and Shell were held up as examples of bad practice by being more than economical with eco.Shell’s ad above was ruled misleading because 'it implied Shell used at least the majority of their waste CO2 to grow flowers, whereas the actual amount was a very small proportion when compared to its global activities'. You get the picture.In fairness to Shell, it is sponsoring the UK Business Council for Sustainable Energy’s Sustainable UK Cities Tour aimed at helping local businesses secure green public sector tenders.Research by Shell estimates the market for businesses tackling climate change at a whopping £2.8bn - which may well explain the over eagerness of its marketing, but also emphasises the massive potential to be exploited by genuinely green offerings.