Expanding Heathrow is unnecessary

Over a fifth of flights from Heathrow are to destinations within 500 kilometres of the airport - destinations easily reachable by train . train(6). Train travel is around ten times less damaging to the climate than flying . flying(7). The number one destination from Heathrow is Paris . Paris(8). The fourth most popular destination is Manchester - with 32 flights per day between London and the city. Transferring these 100,000 short haul flights from Heathrow to the rail network would take capacity back to 1990 levels, significantly reducing our Co2 emissions and largely negating the need for (6)HACAN, (2006) Short-Haul Flights: Clogging up Heathrow’s Runways$1 
(7)DfT estimate that short haul air craft emit 0.15 kg/CO2 per passenger Km. This multiplied by 2.7 (the IPCC’s best estimate for the impact of radiative forcing) equals 0.405. Dft estimates rail on average emits 0.04 kg/CO2 per passenger Km, approximately 10% of 0.405$1 
(8)HACAN, (2006) Short-Haul Flights: Clogging up Heathrow’s Runways.a third runway.