Is it a coincidence that the terrorist outrage in Paris was committed weeks before COP21, the biggest climate conference since 2009? Perhaps, writes Oliver Tickell. But failure to reach a strong climate agreement now looks more probable. And that's an outcome that would suit ISIS – which makes $500m a year from oil sales – together with other oil producers.Yes, it's still about the climate, very much so. But there are also compelling reasons of national and global security to reduce the world's dependence on fossil fuels, oil in particular.The first thing to be said about the terrorist attacks on Paris yesterday is that they are a dreadful crime that deserves only the most fervent condemnation.