The journal Nature Climate Change has published a new study with estimates of last year's global carbon emissions, which topped out at 38 billion tons of carbon dioxide. This is a huge number, and it increases every year, despite all the best efforts of scientists and diplomats.
Global warming is a reality. And although there is room for debate regarding the impact this warming will have on the Earth in terms of temperature increase and sea level rise, the scientific mainstream is united in the assertion that global warming is happening and is a serious problem. And though how serious it all becomes remains to be seen, it is worth noting that former Australian prime minister Kevin Rudd memorably (and, for him, regrettably) called it the Greatest Moral Challenge of Our Time.
I am always intrigued how this issue tends to take a back seat when it comes to environmentalist groups criticising nuclear power. They are very keen to talk of 'safety' and 'protecting our childrens' future', but don't seem to have available the plans for a working fusion power plant and are always quite happy to plug into a power point that inevitably draws electricity from fossil fuel sources. If pressed, green groups wax lyrical about renewable energy, yet seem immune to answering the hard questions that inevitably arise.
The truth is that renewable energy just doesn't cut it. Essentially, wind, power and tidal are just too diffuse and too unreliable. In practice no large country or city can expect to get more than 10-15% of its power from renewable energy. The problems of distribution, storage and base load provision are just too insurmountable. Germany is finding this out right now.
Just for fun, let's do a little thought experiment with wind power. The electricity generating capacity of Japan in 2010, according to wikipedia, was 283 gigawatts (GW). A typical large wind turbine has a capacity of 3 megawatts (MW), and needs spacing of 6-15 rotor diameters. Generally they are placed 1-2 kilometers apart. As turbines only produce about 15-20% of their capacity on average (and often less than that) to produce 283 GW (283,000 MW) you would need 471,000 huge turbines spaced out at least 1 kilometer apart. This would go around Japan's coastline (34,751 km) more than 13 times, extending 13 km inland, and pretty much making the archipelago uninhabitable. It would cost tens of billions of dollars and be a construction effort rivaling anything yet produced by humanity.
And what you would do when the wind doesn't blow, well, I can't imagine.
The problems are much worse for developing countries such as China and India, which can't supply more than a small percentage of their power from renewable sources now, let alone in the future with a vastly increased electricity demand. India alone has 400 million people without electricity.
It is obvious that without a reliance upon nuclear energy, the vast bulk of future electricity production will come from fossil fuels, making a mockery of the Kyoto protocol and other international agreements intended to control global carbon emissions.