The climate change challenge

Cities consume 75% of the world’s energy and produce 80% of its greenhouse gas emissions.  However, whilst the activities and buildings within cities contribute heavily to carbon emissions and climate change, they are also proving that they can be part of the solution. 
Although not usually considered as being green, cities in the UK are focusing all of their attention on lowering carbon emissions and the results are setting a benchmark for the rest of the country.
UK cities are currently responsible for 30% of the country’s carbon emissions, which represents 140 million tonnes annually.  This has been recognised and they are now leading the way by cutting energy use, reducing CO₂ emissions and supporting the growth of the country’s renewable and low carbon industries.
Environmental systems manufacturer Mitsubishi Electric has produced a free guide which examines the options, legislation and plans influencing the UK in an aim to create sustainable cities.
“By increasing renewable energy supplies within cities and addressing the energy efficiency of buildings, the core cities have the potential to make a large contribution to the UK’s overall carbon emission reductions,” said Commercial Director Donald Daw. 
“We are hoping that the cities programmes will provide vital research, including a breakdown of emission totals and where they originate.  This will provide a baseline and enable us to identify where the most impact can be made to reduce carbon emissions.”
A Low Carbon Cities programme (set up in late 2007) aims to introduce new measures and initiatives which could include renewables, greater insulation, and trigeneration – producing power, heat and cooling from a single source. 
As the biggest city in the UK and the capital, London is keen to be at the forefront of the climate change challenge.  Consequently, a specific London Plan makes significant growth projections in the domestic and commercial building sectors up to 2025 and predicts that if buildings are constructed at current CO₂ levels, this could lead to an increase in 5.1million tonnes of CO₂ per annum. 
“The London Plan is not simply an environmental goal, but is part of a drive to build businesses in the renewables and CO₂ reduction sector in and around the London area,” said Donald.  “As a result of this dedicated focus, London has the highest energy efficiency standards of any city in the UK and is leading the way on low and zero carbon development.”
This plan aims to ensure that, at a minimum, new-build will be 30% more efficient than the city’s existing building stock by 2025.  If these targets are met, there could be a CO₂ saving of 1 million tonnes per annum.
As part of the move towards more sustainable cities, the plans also focus on building design changes, such as natural ventilation, passive solar design, use of sustainable drainage, and rainwater harvesting.  The plan favours decentralised energy supply as a mainstay of its carbon reduction policies.  This includes the use of combined heat and power (CHP) as well as combined cooling, heat and power.