When we fly, drive or take a cruise we are all contributing to carbon emissions. As we all know the emissions from transport account for a significant percentage of what we pump out into the atmosphere. In the European Union, for example, about 27% of all emissions come from our travel.

As a result many organisations offer you the chance to "offset" the carbon you produce for the journeys you make. The great part of carbon offsetting is you can quite easily calculate how much carbon you are likely to use, depending on your mode of transport and then you pay extra money to cover the cost.

Often that money will go direct to climate change mitigation projects in developing countries and that is a good use of new money. These will often include projects that aim to "soak up" the carbon you have produced through tree planting, for example.

But carbon offsetting has its limitations. Since the message behind paying for the amount you pollute can be (wrongly) interpreted as "it's OK to take a domestic flight as long as you pay to offset the carbon you use".

Ten years ago that may have been an adequate argument-but we are now in an unprecedented climate emergency. As a result we need to drive down carbon emissions; rather than simply pay for the privilege of creating them (which risks maintaining the status quo).

So carbon offsetting is a great tool for helping us to think about the amount we pollute and then providing us with the ability to pay some money to cover some of the pollution costs. But we need to focus more on reducing our travel. Only by reducing unsustainable travel will we start to cut carbon.

That means more public transport, more bikes, more walking, more car sharing, more zero emissions cars, no domestic flights (unless you have no choice) and no cheap cruises on highly energy-demanding ships...or cheap holiday flights on budget airlines.

It is not a question of whether we should offset or reduce our unsustainable travel footprint; it is a case of doing both; and knowing that it is only by doing both-and fast- that we will truly be able to curtail our still growing travel emissions.

The next few years will be critical and unless we take radical action, the global carbon emissions from transport will continue to grow resulting in potential extinction for many species. As ambassadors of the planet we can choose to do little and pay the consequences or act as if there may be no tomorrow and reap the dividends.

Andy Lester is Head of Conservation at Christian environmental group A Rocha.