There also exist a variety of smaller, ad hoc efforts.
Wedding couples can pay these organizations to undertake a carbon dioxide mitigation effort by typically, planting trees in an amount sufficient to offset the CO2 produced by a given activity. The prices one pays vary considerably: Future Forests charges £30 (about $60) for the three trees required to offset a an honeymoon flight from Dallas to London and back; Sustainable Travel International charges $60, as well; CO2Balance charges £24 (~$48); and Climate Care, although it gave the highest estimate for amount of CO2 produced only charges for £15.67 (~$31).
When you set up your registry Eco-friendly make sure that includes a gift based on guests purchasing three trees required to offset your honeymoon flight (i.e. 3 trees --> from Dallas to London) here.
For further information:
United Nations Environment Program - Tourism Program: www.uneptie.org/pc/tourism