When one considers the complexity of climate modelling, the surprise, to me, is that "97% of climate scientists agree that climate-warming trends over the past century are very likely due to human activities"; IPCC defines 'very likely' as 95% certainty.
As computing power increases, the predictions will become more accurate. Incorporating climate data and observations as they become available into the model helps refine the results and predictions. An example of this is the failure of the model to explain why global average surface air temperatures did not rise as expected between 2001 and 2013, in spite of enormous amounts of CO2 pumped into the atmosphere.
Professor Matt England at the Climate Change Research Centre, University of South Wales, Australia. explains in this You Tube video that the model did not properly reflect the unexpected strengthening of trade winds during the period, which led to the transfer of more of the heat to the western Pacific Ocean. Once this data is incorporated into the model the predicted surface air temperature matches what is observed.
Fossil fuel is stored energy that took millions of years to accumulate. At the start of the industrial revolution we began releasing this energy at an enormous rate to power our civilization. Energy accumulated over millions of years is being released in a few hundred years. It should surprise no-one that such massive intervention in the carbon cycle produces global warming.
It is high time we accepted the science - climate change is real and man-made - and started to implement energy saving measures in everything we do. We need to embrace renewable energy and in so doing drastically cut our emissions of greenhouse gases. Only through this can we limit the devastation that will result if global warming is to exceed substantially the critical threshold of 2C.
In fact the latest IPCC report makes it clear that whatever we do from now on, we are likely to go beyond 2C. That does not mean we should do nothing, as the worst effects of warming - extreme weather conditions and rises in sea levels - are directly dependent on the extent of global temperature rise above 2C.
Nicholas Stern, Chair of the Grantham Research Institute on Climate Change and the Environment at the LSE, in a recent article in the Guardian (14-02-2014), comments on his 2006 review on the economics of climate change thus:
"In fact, the risks are even bigger than I realised when I was working on the review of the economics of climate change for the UK government in 2006. Since then, annual greenhouse gas emissions have increased steeply and some of the impacts, such as the decline of Arctic sea ice, have started to happen much more quickly. We also underestimated the potential importance of strong feedbacks, such as the thawing of the permafrost to release methane, a powerful greenhouse gas, as well as tipping points beyond which some changes in the climate may become effectively irreversible."
The 2006 review makes the point that countries don't have to choose between economic growth and taking action to arrest climate change. The review tells us that:
"Without action, the overall costs of climate change will be equivalent to losing at least 5% of global gross domestic product (GDP) each year, now and forever. Including a wider range of risks and impacts could increase this to 20% of GDP or more, also indefinitely. The Review proposes that 1% of global GDP per annum is required to be invested to avoid the worst effects of climate change. In June 2008, Stern increased the estimate for the annual cost of achieving stabilization between 500 and 550 ppm CO2e to 2% of GDP to account for faster than expected climate change."
Thus, taking action to stabilize climate change is cheaper than doing nothing. Moreover, such actions - energy saving measures and investment in renewable energy - are the only way of having a sustainable economic growth.
The science is 'unequivocal'; climate change is real and human-induced. Embracing the renewable energy route will usher in a new industrial revolution that will be in harmony with our environment, and in so doing will safeguard the future of humanity.