The second car thing is something that is a little bit awkward. It's not really a good idea to run two cars, but in reality we have little choice. We live in the middle of nowhere, and Nigel needs a car to get stuff for the farm whilst I need a car to go to work. Hardly massive mileage!

We've minimised the impact the car is going to have on the worlds resources per se by buying an older car and therefore reducing the amount of energy and CO₂ that would have used to build a new one. I'm struggling to get exact values, but the reports I've found suggest that the energy to build one car is approximately the same as it will use in the first 100 000 miles or 3¹/₂ years. The car we've bought has already done some 180 000 KM (or about 110 000 miles), so the embedded energy in the car has already been well and truly paid for over it's 13 year life! By buying a car that has been well used, loved, and maintained (so it isn't inefficient) we are saving some 36 tonnes of CO2 being released into the atmosphere. A new car would make a serious dent in our attempts to reduce or CO₂ footprint!

The next thing we are doing is for two reasons. We are planting some trees on our land - the first batch of many we want to plant. They are broadleaved trees and should live for many years. We chose fruit trees so that we also got a useful crop from them. The trees were raised at a local aboretum and are mainly varieties that are local to the Skåne region, as a result they are very hardy to the weather around here and should live for many many years.

It's easy to just plant a tree and think "that's it, I've offset my carbon", but a closer look shows it's actually a little harder than that!

One tree, according to Carbon Footprint , will  offset about 730Kg of CO2 over its 100 year lifetime. To offset our previous 4.7 tonnes of CO₂ per year that would mean planting 6.5 trees per year. Note, that is each and every year I would need to plant 6.5 trees. Not a one hit that's it. Every year. And paypack isn't reached until 100 years time...

On our land that just isn't practical, we'd run out of land very very quickly! We're planting 9 trees initially, they will absorb some 6.57 tonnes of CO₂ over their lifetime. That means each month my 9 trees are going to offset 5.4kg of the 305 kg of CO₂ produced by my car year in year out.

 Put like that, we've got an awful lot to do.

 Like plant another 508 trees.

Update

The possibility of planting enough trees to offset your annual production of CO₂ seems virtually impossible. With the area required by each tree to grow, it's just not a realistic solution.

There are many schemes to enable you to have your trees planted elsewhere. Be careful - some schemes just protect trees that are already there, they are not actually adding new trees. It's also incredibly expensive to have your trees planted in the EU - typically it seems to be around £10 per tree.

There are alternatives as a short term fix (at least, I personally see them as short term). One of these is carbon offsets. With these you work out how much CO2 you produce each year, and then donate the money to charities, foundations or other organisations, and the money will be used to "buy" the production of someone else. For example, if I pay money then someone else will reduce their CO₂ production by the required amount. I have mixed feelings about this, part of me is relieved that there is a solution that allows me to reduce my carbon impact, but another part feels as if I'm cheating by getting someone else to do my work for me. This could be through investing in renewable energy schemes, energy efficiency schemes, and also planting new forests. 

One such scheme is run by Climate Care . It's very easy to get worked up about it having to be through a charity. Climate Care isn't - it's a company limited by guarantee in the UK. It has the support of people and groups such as Forum for the Future, Oxford University Environmental Change Institute, & John Elkington who wrote "The Green Consumer Guide".  It goes into genuinely reducing CO2 output, and not merely paying for countries commitments they've already made under Kyoto or EU Emissions Trading. The scheme is overseen by a panel of experts that I'm happy to believe in. And it doesn't have to be expensive - it costs as little as £7.50 per tonne.