Global warming is pretty much an accepted fact of life in the 21st Century, but the causes of it remain a little controversial. There are two schools, it seems. The first, popularised by the likes of Al Gore, is that our carbon emissions are trapping heat within the atmosphere and causing the planet to heat up. The second school of thought, championed by the makers of programmes like The Great Global Warming Swindle (see also), is that the world goes through natural heat cycles, and that the sun and the clouds are more important factors than CO2. But both agree that the world is heating up - so why is only one side calling for change?

In the last couple of years there has been an explosion of concern over CO2 emissions. An Inconvenient Truth and Live Earth have played a role in that, along with a media increasingly showing an interest in environmental affairs. An informed public demands informed politics and, at least in certain parts of the world, politicians are falling over themselves to go green. Reducing emissions is suddenly a priority. The political parties trade percentages and targets, and every company wants to boast about how they're reducing their CO2. On the other hand, a smaller but not insignificant group of scientists resist the consensus. To quote from the aforementioned Global Warming Swindle documentary, 'CO2 is irrelevant'.

What I find interesting is how the debate has polarized around the issue of whether or not climate change is anthropogenic - is it caused by human activity, by industrialization? One side says man-made co2 is causing global warming, the other side says it's caused by the sun, and although we may have reached a scientific consensus, it isn't universally accepted by the public. According to recent MORI research in the UK, "40% question our ability to predict the climate system, while as many as 56% believe that the jury is still out on the causes of climate change." Nobody wants to make sacrifices over uncertain science. A man interviewed for the research put it this way: "You just don't know who to trust, it's like you've got no idea what's really going on... so I'm just going to ignore the situation."

But here's the crazy thing - neither side are denying that global warming is happening. They disagree on why it is happening, but climate change is happening. Ignoring it is not an option. What I don't understand is how being sceptical about anthropogenic climate change is a license to do nothing. Even if it turns out in time that Al Gore and the IPCC and the rest of us have got it completely wrong on CO2, well, the climate is changing anyway. Deforestation, soil erosion, and species extinction carry on. Fresh water becomes scarcer, arable land is lost, and huge migration problems still happen. So where are the sceptics tackling those problems? All the calls for action come from those who believe that humans are having an impact on the planet. Those who say it is natural manage to wash their hands of it. Where are the scientists saying global warming is not caused by CO2 emissions, but who are still working on solutions?

It's like two people finding their kitchen on fire. One says, "it's my fault, the candles I left burning on the table must have set the tablecloth on fire. We'd better put it out." The other says "It's a perfectly natural occurrence, the burning tablecloth must have lit the candles, we don't need to do anything about it." Either way, whoever may to blame, the house is on fire.

I think we're in danger of becoming fixated with CO2. I believe we need to reduce our emissions of greenhouse gases, no mistake, but the environmental crisis is bigger than CO2. There are multiple reasons for action, beyond climate change. Even if not just carbon emissions, but the whole idea of global warming were false and the earth was to get colder in future, we still have a resource problem. We still may have just seen oil production peak. We're still taking too much from the earth, and putting too much of the wrong things back into it.

I'd kind of hoped the debate was over, but apparently 56% of people in the UK believe the experts are still divided. As George Monbiot wrote earlier this week, "everyone is watching and waiting for everyone else to move." The important thing is that whichever side of the climate change debate you find yourself, no matter how confused we may be over why things are happening, there are no excuses for inaction. The one thing we definitely can't do is ignore climate change and hope it goes away.