Killing two birds with one stone
The two birds: My wife's desire for additional landscaping; and, your carbon guilt. It's really simple. You go to The CarbonNeutral Company website and calculate the amount of the carbon emissions resulting from your daily commute. Note the estimated values for carbon mitigation. You then go to PayPal and send me one of the amounts shown. Don't worry, I'll accept whichever amount you select. After receipt of your funds, I'll send you a certificate - suitable for framing - stating that I have declared your commute carbon neutral. My wife and I will then go to our favorite nursery and buy trees and bushes. Of course, we'll snicker behind your back. But, hey, you'll never know.