To prove I'm a man of my word, and that I commit to protecting the environment when at all possible, here's the carbon offsets I purchased for my flight to London from Winnipeg. I've also purchased carbon offsets for my flight from London to Amsterdam. I think it added $3.00 to that flight. Carbon offsets don't add a lot of cost to your flights. The flight to London contributed to a reforestation project in BC:

Forest Restoration Project:

Our forest restoration project in Maple Ridge, British Columbia is pioneering the development of credible and effective climate change mitigation and ecosystem restoration products. In 2006, this project developed over 200,000 tonnes of carbon credits in the District of Maple Ridge over an area of approximately 83 hectares, and involved the planting of over 25,000 indigenous Douglas Firs, Sitka Spruces, Western Red Cedars, Western Hemlocks and Cottonwoods. It is a project that aimed at accelerating the natural process that often takes hundreds of years, whereby a degraded scrub and brush land ecosystem restores itself to its natural state with indigenous species. The degraded forests in question are formerly first growth forests (full of Spruce trees and the like) now overgrown with invasive brush, bushes, and Alder trees. This project consists of planting a strategically-placed heterogeneous mixture of native species, managing them until they are firmly established and reach a certain level of maturity (about five years), and then letting the native trees outgrow the existing brush land, which eventually eliminates the invasive species that are present. Our project provides wildlife habitat and biodiversity, prevents soil erosion, helps purify water that flows into streams and lakes, provides food, shelter and recreation, and produces demonstrable carbon sequestration that would not otherwise have taken place.