Here are some useful links on climate change and the environment from the government, Transport Focus, and other organisations. 

Reduced bus emissions and improved air quality in Brighton & Hove - case study
Transport Focus - Bus passengers’ priorities for improvement
Transport Times - Why the Euro VI bus is essential to the success of Clean Air Zones
Carbon Independent - emissions from cars
CBI - Powering the UK's low carbon future
DEFRA - Air Quality Management Areas
Environment Agency
Vehicle Certification Agency - Fuel Consumption Guide
Transport for Quality of Life
Friends of the Earth
Global Action Plan
Transport for South East - A bold vision for a brighter future