IN answer to Sue Stephen's question about the lack of garden birds (Letters, March 9), this is due to a number of things – extinction of insects, use of pesticides. Scientists in Germany have discovered an area where 75 per cent of insects have died out. If it is happening in Germany, it is happening everywhere. When there are no insects, there is no food for adult birds to give to their babies. Rachel Carson explained it quite clearly in her book Silent Spring. This was published in 1964, so this problem has been well known in the scientific community since then.

There is no excuse for not knowing that life is a green chain, a web of life, a jigsaw puzzle, where there is a place for everything to fit together. If you upset the balance, you endanger life on the planet, as we have seen. Worms are also dying out. We need worms to aerate the earth so plants will grow, we need insects to pollinate plants so that we can have food crops. No insects means no food. One species we certainly do not need on the planet is mankind, whose only purpose seems to be to wipe everything else out.

The European Union at the moment is trying to stop a well-known American chemical company from selling its toxins here. As long as we allow chemical companies to experiment on us, we have no future. Unfortunately, Brexit has not frightened the birds away, if would have been simpler if it had.

Margaret Forbes,

Corlic Way, Kilmacolm.

YOUR article on the potential effects of a no-deal Brexit on the lucrative export business by Spanish farmers to the UK and cites Germany as being Spain's biggest market ("Almeria fears for crops", The Herald, March 8). In fact, in 2018 German media and consumer protection activists exposed the health, environmental and human costs of cheap vegetables from Spain being sold in German discounter supermarkets. They highlighted the excessive use of nitrogen fertilisers to compensate for nutrient depletion in the soil because of intensive harvesting of land, in some cases up to four times per year. Apart from the health hazard this has had a devastating effect on rivers and lagoons in Spain due to the agricultural run-off. Investigations found that 30 per cent of farmers in Murcia did not filter nitrate from the ground water that they were using for irrigation as it added to production costs and reduced their price competitiveness.

Morag Black,

3 Leeburn Avenue, Houston.

WHY are we making the issue of disposable plastic drinks cups so complicated ("A new move to meet the coffee cup challenge", The Herald, March 7, and Letters, March 9)? We know that plastic uses hydrocarbons that need to be left underground if the world is not to fry and that their slow rate of decomposition pollutes land and sea. The simple and most effective solution would be to ban them. People who regularly buy takeaway drinks would soon learn to carry re-usable cups and for those without, outlets could sell returnable cups at a price which would encourage their return. Any outlet selling such cups could be placed under a legal obligation to take back any re-usable cup presented to it. Problem solved! Next step, scale up the approach to all plastic containers and packaging.

The reason our governments don't take such an approach appears to be because of the neo-liberal conviction that change can only be achieved through individual choice and the markets. This drives us to spend endless time and energy working out how to change people's behaviour against the odds, the odds in this case being the vested interests of all the businesses involved in the plastic cup supply chain. The public sector is left to pick up the pieces, devoting significant resources to litter collection and recycling which often doesn't work as much recycling ends up being "contaminated" and deposited in general landfill. As long as cheap disposable cups are available, any drinks outlet that tries to do the right thing risks pricing it out of the market while there is no incentive for those people who do drop litter or ignore recycling facilities to change their habits. Its time all our politicians started to challenge the primacy of the "markets" and put the world first.

Nick Kempe,

23 Queen Square, Glasgow.