I congratulate the 6,000-odd petitioners for raising this with us today. I think a similar number signed a petition when I was initially elected to chair the climate change committee. There were similar misplaced security concerns at the time, and I was called in for a special discussion about how we were going to deal with a concern that the committee was going to be overrun by protesters, which I'm pleased to say didn't happen, any more than it did on the more recent occasion—albeit, in the case of the first committee that I chaired, we scheduled it for a 9 a.m. start on the Thursday immediately after Wales had been playing the Euro 2016 semi-final the night before. We didn't have any protesters at all.

We see, though, in the petition the demand that we have—the emphasis on net zero. There is one thing that I'd like to understand about this, and I don't know whether any other Members will be able to assist me in their speeches, or otherwise, or whether this is clear from the petition. By 'net zero', do they mean net zero within the United Kingdom? So, that's taking into account extra tree growth—which is certainly something that I would like to see and the offsetting from that—but not taking into account international offsetting. I'm not clear quite what's required. The UK position appears to have been that they are including that international offsetting, which makes it an awful lot cheaper to obtain this goal. When you get very close to eliminating carbon emissions, even if some are offset on a domestic basis, it gets an awful lot more expensive at the margin to do so because you've already taken the low-hanging fruit. 

One thing I think is very important in this debate—and I think some of the petitioners recognise this—is to understand how far the United Kingdom has come on this since the Kyoto commitment. We are now, I think, just over 40 per cent below 1990 levels of emissions, and that is virtually the largest reduction seen anywhere in the world, and I think that's something we should recognise and take pride in. The current legislation is until 2050, the 80 per cent reduction—basically, that would mean the same reduction again, but actually as a proportion or a percentage, that is a higher reduction. It's also more difficult because the easy gains from closing most of the coal-fired power stations and a lot of the heavy industry that we had in the 1980s, at least to an extent, but no longer do—that has already happened. So I'd like to ask to what extent we want to achieve this by paying other countries to do this for us on the basis they can make carbon reductions for less cost than we can in this country once we have got so close to the target that is projected.

I'd also like to just have people consider what is actually involved if we're going to get to this. It's one thing to declare a climate emergency—. And initially I thought the First Minister was saying it was just declaratory, and he wasn't planning any changes of policy, but then when he made a statement in the Chamber about the M4 decision he did emphasise climate change issues, albeit he hadn't mentioned those in the decision notice. So I'm still a little unclear on the extent to which this is changing Welsh Government policy or remains merely declaratory.

But for some of the big issues, if you want to move to anything like this target, you are going to have to rip out gas boilers from millions of homes and replace them with an alternative. Now, ground source heat pumps is one option that has seen some take-up, but broadly, if you want to do this at speed, if you're going to have electric central heating instead of gas central heating, at the moment that costs at least three times as much, and I just ask Members to consider how plausible it is, going to persuade or potentially even coerce constituents to make that change. I think we need to consider this as well as looking at what other people are doing internationally, and I think to the extent that people look to us for a lead—and I don't know the degree to which they do or do not—there may be some value in that.

I think we're at 1.8 per cent of global emissions now, and if the impact of this is going to be such economic self-harm that we are no longer to export many of the goods we are, or are going to struggle to compete with other countries that don’t take the same steps, then it will be less attractive than otherwise. Similarly, if we do see technology develop to such an extent that we can cost-effectively remove carbon from the atmosphere, then that makes it much more attractive to go down this route. On the other hand, if that isn't a technology that becomes cost-effective or doable, then the cost-benefit trade off for pushing this direction will be less attractive. Thank you.