You read about "carbon offsetting" and perhaps you wonder if it's all rubbish. Well, there are some figures around and some facts around and some myths around - and a LOT of predators who will bend you over for carbon credit input dollars. Here's my take so far:
To clear your carbon debt for the year, some articles claim that you'd have to replace 111 lightbulbs with CFL bulbs. They say you'd have to switch to smaller hybrid cars for X years to clear the debt for one year, and so forth.
In reality, every light bulb you replace with a CFL or CCFL bulb is immediately reducing your carbon debt. If you put the petrol-guzzler in the back of the garage and the scooter and the Prius near the front, you are immediately reducing your carbon debt. If you set your air conditioning to two degrees warmer in summer and your heating to two degrees cooler in winter, the effect is immediate, you use less fuel and create less pollution. If you put water pressure reducing discs in your shower heads and take shorter showers, that is something you can do right now which takes effect right now.
"But," I hear you say, "that only reduces the carbon debt, I want to cancel it!"
Well, you can offset all you like by adding trees or other activities like that but the sad truth is that just by living you add to the debt, it's unavoidable. And you can plant a tree to offset your carbon debt now but it won't produce any benefit for a few years, and even then it is a bit of a gamble if it will balance your carbon debt or will be way behind the curve.
Also, the carbon debt you acquire is out there and then you add an input, but the unavoidable thing is that for some period oif time, your pollution load *is* added to the atmosphere for a certain period, it's like injecting yourself with snake venom and then a shot of antivenene later - the venom will have been there for some period and killed certain nerve and muscle cells and no amount of antivenene will repair that damage.
So cast a jaundiced eye on the companies that say they will repay your carbon debt because A) they need money to survive and B) they don't generally care about global warming beyond how many dollars they can extract from you and C) they will want more than just "a little" money for their version of "saving the world..."
I'm not saying that inputs are bad, I'm saying that you will need to look carefully at what methods you should use, whom you should trust - and in the meanwhile, reduce your debt now so that there will be less to balance later.