I have not read the offending document and normally would not comment on issues relating to the range and migration of birds of which I know little. I wonder at the need of some species to migrate and whether  the deep seated compulsion to depart from winter climes can be ever influenced by climate change.  While, perhaps, it is easier to understand why birds flee an approaching winter it bewilders me that they choose to go back when food remains plentiful and climate  benign. Why embark on a hazardous and potentially unrewarding journey? It seems to me that irrespective of the progression of climate change the birds are so immutably programmed to compass and clock, they will fly irrespective of altered or changing circumstances or degree of risk.

However, my musings are not the reason for my intervention. As a climatologist with 40 years experience of African weather with half of that time spent as the chief atmospheric scientist responsible for addressing climate change impacts under the World Climate Programme, I can say that while it is probable that climate is changing as a consequence of anthropogenic greenhouse gas emissions, there is limited understanding of the likely speed of global warming or of the level it might reach globally irrespective of mitigation policies. Furthermore, the nature and extent of regional or national climate change, especially in the tropics are not understood at all beyond imperfect model projections based on limited, incomplete and imperfect data sets. It is not possible at present to identify with any certainty, a climate change signal in Africa. The African climate is highly variable and it is this extreme variability often influenced by large scale ocean-atmosphere interactions that are currently more significant than the projected anthropogenic climate change. In my opinion, it is not possible to make believable projections of altered ranges or movement of bird species based on imperfect predictions of regional climate change. Destruction  of habitat and other effects of human population increases are having, and will have a profound negative effect on nature including wildlife and birds. Climate change, in comparison, has currently little impact and even when it changes sufficiently to be a factor in bird behavior, I am afraid people will still wield the greater influence. Environmental groups in Kenya are fighting a battle to protect the Tana River delta. It is an important staging area for migrating birds, It is home to important and rare flora and fauna. Pastoralists use the abundant grazing and water as a refuge against regional drought, It has the potential to become a valuable income-generating eco-tourism site. Yet it is threatened by many local and multi-national developers who would clear the forests and convert the pastures to large-scale rice and sugar cultivation for export, Others wish to mine it for its minerals and a foreign government seeks the land to grow food for its country in exchange for engineering development . Nature there will be destroyed for ever. Avian migratory routes  and habitat ranges will be forced to change but it will not be a consequence of climate.

Peter Usher   

Hi all