Summer 2001

Coastal Warming

Article by David Colbourne (on secondment to Sefton Council Energy Team)

A brief history of the global warming policy saga.

The phenomenon of global warming first attracted mass media attention at the Rio 'Earth Summit' in 1992, where the United Nations' Framework Convention on Climate Change was first motioned. This required developed nations to restrict their Greenhouse Gas (GHG) Emissions to 1990 levels by the year 2000. In 1997 the UK played a pivotal role in the Kyoto agreement which set out a target of 8% reduction in GHG emissions by 2008-12 (using the 1990 baseline figure). Further to this the EU agreed collectively to achieve an 8% reduction and therefore allowed individual states to meet the commitment jointly. The UK has taken a lead on this issue and set itself a target within the EU of 12.5%. This is further supported by a UK government pledge to reduce emissions of Carbon Dioxide (CO2) by 20% by 2010 (CO2 being the most important of the greenhouse gases). These are demanding targets but there are strong calls to suggest that cuts of 60% should be achieved by 2050, so this first stage can only be seen as a stepping stone. In support of this the UK has also set itself the target of generating 10% of its electricity from renewable sources by 2010. In its Green Paper of 1996 on Renewable Energy the EU suggested a target of 12%.

So why has all this barrage of policy been brought about?

Many Governments are taking heed of the warnings and applying the precautionary principle in face of unvalidated science. When it comes to Global Warming the science is difficult to understand as we learn from observation and we do not have a good example to study, instead we must observe from history before man and as we go along. This has meant that the debates have been drawn out and very technical. However in many cases some of the key issues predicted are starting to be observed.

  • Climates are changing (Spring is estimated at six days earlier; the last decade has seen the hottest seven years on record)
  • Species are moving (Cod are moving further north away to colder waters; more varieties of Mosquitoes are being found in the UK)
  • Storminess is increasing (many more flood events and severe gales)
  • Sea level rise (sea level rise at Liverpool has been observed around 6 cm in the last 50 years)

    The potential impacts that we could experience as a result of these changes are varied and sometimes surprising. As habitats and species are inextricably linked the threat of species moving into our area or out of our area as the climate changes could severely influence the make up of the natural coastline as we know. The northwest report, Everybody has an impact identified that the region's coastal areas could see an expansion in more temperature and moisture dependant species such as blanket bogs, beech trees, reptiles and insects. However the unpredictable coastal dynamics could lead to extensive beach and dune erosion and loss of prime ecosystems such as mudflats and salt marshes as they become flooded.

    A recent report by the Woodland Trust identified a serious threat to coastal forests in the southeast due to drier summer conditions. The predictions for the northwest are not comforting. We should experience reduced rainfall in summer but this will be offset by increased rainfall in winter, giving a net gain in rainfall. This is not all negative, there are some economic benefits as the summers become drier and this has a positive impact on tourism, there will be more demand for outdoor activities and terrace cafés.

    Sea level changes

    Sea level changes are perhaps the greatest physical threat to our coastal environment. The main concern is that, as a consequence of global warming, sea waters will expand as they warm up, and as the ice caps melt there is more water to expand. We already know that levels have been rising locally by about 1.5mm a year for the last 100 years. We cannot confidently predict that future rises will be at the same rate and the feedback mechanisms are poorly understood. For example the melting of ice water leads to two possible outcomes. Firstly that the cool water counteracts the warming of the seas or that secondly the addition of melt water feeds the expansion of the seas by increasing the volume of water in the sea.

    Due to this uncertainty its difficult to be confident that new flood defences will be effective. MAFF have developed strong tools to allow for the changes but hard engineering solutions that are oversized can have their own local impacts. Some researchers estimate that tidal surges in the Irish Sea will treble in the next 50 years as sea levels are predicted to rise by up to 15cm. This is further compounded by the increased wind speeds that will increase wave height by 2mm a year.

    It is worth noting that sea defences only have limited application; we have already altered our coastal region significantly. Much of the area of West Lancashire, behind the sand dune system on the Sefton coast (stretching up to Martin Mere) is reclaimed land. In fact this was once the largest lake in what is now England. Without the current coastal protection and inland drainage this whole area could be at risk from tidal surges in the future as it is all land below mean high spring tide.

    The direct effect of climate change on our wildlife could have strong implications for our protected sites and national species. A Friends of the Earth report identified that the main British species threatened by climate change included natterjack toads, sand lizards and bitterns.

    The advantage we have is that these processes are relatively slow and we can hopefully prepare and mitigate for them. You can also help with these threats by "doing your bit". Sefton Council have many initiatives aimed at reducing the impact of climate change by reducing CO2 emissions in their own buildings and by helping residents in their own homes to reduce energy use.

    The council is also actively involved in the North Merseyside Biodiversity Action Plan which aims to assist in the preservation of the species we have.

    David Colbourne
    Energy Management Officer
    Technical Services
    Sefton Council
    Balliol House
    Balliol Road
    L20 3NJ
    Tel: 0151 934 4216

    Key contacts

    Energy Efficiency advice 0800 512 012
    Energy Team 0151 934 4216