Being pragmatic also means recognizing that economic growth and action to tackle climate change are not mutually exclusive — a point persuasively made in the recent New Climate Economy report produced by Lord Nicholas Stern and others. And it’s about recognizing how effective carbon pricing can help to tackle emissions at the lowest possible cost to consumers and with the lowest impact on economies.

What other steps can we take? Already acknowledged is the importance of shifting our power generation systems away from reliance on coal, by far the most polluting fossil fuel. That means, in part, a greater role for cleaner natural gas, as well as a steadily growing role for renewables, even if experience shows that growth necessarily will be slow.

Innovation, too, is essential. As we navigate what will be a decades-long transition away from a fossil fuels-dependent energy system, new technologies can play a crucial and transformative role. One example is CCS —the process of capturing carbon dioxide from man-made sources such as power stations and storing it safely deep underground. The ability to innovate is also the reason why – along with our global reach, our capacity to invest over the long-term and our deep experience of working in partnership with others – companies such as Shell won’t be mere witnesses to the coming energy transition, but essential participants.

In announcing the climate change agreement with China, Obama has rightly acknowledged that the objective is “ambitious but achievable”. Accelerating any kind of planet-wide energy transition, while mitigating something as complex as climate change, will always be ambitious, but, with the right pragmatic approach, the right innovative thinking and the right collaborative action, it is both highly desirable and, now, seemingly more achievable.

The author is chief executive officer at Royal Dutch Shell plc.