This is a fast-moving seesaw of a ride through the latest schemes to combat climate change. From the title, one would expect it to be cheering. But Tim Flannery, while an excellent writer, is also a scientist, so he is given to pointing out the downsides to new and bright ideas as well as being hopeful about their possibilities.

Flannery’s first book, The Weather Makers (2006), was very influential mainly because he turned the science of climate change into a graphic read and spelt out the global consequences in the clearest fashion. This latest excursion into the same area is supposed to be more optimistic, judging from the title. And to be fair there’s much to be cheerful about. There are some very clever people out there devising brilliant schemes for getting carbon dioxide out of the atmosphere and saving us from the worst effects of climate change. All that is needed is to scale them up sufficiently and we will be saved – or could be – if we act fast enough.

There are plenty of ideas to choose from. Perhaps the most unlikely, yet most appealing, is seaweed farming. This not only takes large quantities of carbon dioxide out of seawater, so reducing the acidification of the oceans, but also can be used for biogas production. The seaweed farms make a haven for shellfish and a nursery for commercial fish, and provide many by-products – but obviously from the climate perspective it is biogas as a substitute for fossil fuels that matters. The only problem is scale. There would need to be seaweed farms covering 9% of the oceans to solve the problem of climate change.

But this book is more than a run-through of possible solutions. It is an update on the latest science and how close we are to catastrophic climate change. It was written before the Paris climate talks of last December, about which Flannery was not hopeful. In the event the result was far better than most people had dared to hope. This does not detract from Flannery’s main message, however – that it is lack of leadership from the politicians that is our main obstacle to tackling climate change, not lack of technology.

Many of the examples he uses to illustrate this are from Australia. Flannery’s native land is one of the most seriously affected by climate change, yet in recent years it has had a government entirely sceptical about climate change and wedded to the interests of the coal industry. The worst offender, former prime minister Tony Abbott, was in office when Flannery wrote the book, but he has now been succeeded by Malcolm Turnbull – a moderate by comparison, but by Flannery’s standards still not up to the job.

The book examines a lot of technical “solutions” and geo-engineering techniques, such as putting iron filings in the sea to stimulate plankton growth, and thus storing carbon on the seabed. Many of them won’t work or have potentially dangerous side effects that render them worse than useless. The best solutions always seem to come down to producing less carbon dioxide in the first place and finding substitutes for fossil fuels. In the end this is a cheering read because the signs are much better now than they have been for a long time. The message is that we really could save our children from a terrible future – but we need to try harder.

Paul Brown is co-editor of the Climate News Network and is a former environment correspondent for The Guardian.