Guardian: As the recession bites, the economies of many countries are slumping. But is the consequent fall in demand for energy and goods significantly reducing greenhouse gas emissions? In Europe, the emissions trading scheme provides a clue. Firms with high levels of pollution must buy carbon credits, the price of which has fallen below 9 from 30 last summer. Analysts say the price drop reflects a slowing demand for credits as companies scale back production and cut their carbon …