Aristotle wrote, ‘What it lies in our power to do, it lies in our power not to do.’ A practical example can expand this thought further. One example is from Somerset, England, where flood defence system did not work properly because of extreme weather condition and lack of political will. Another example is from Cambridgeshire, where land lies lower than Somerset level and nine feet below the mean sea level and never flooded. The reason is that whole landscape is manmade and reclaimed from the fenland in the 17th century. What happened at that time was that the rivers were straightened and diverted, new drainage channels built, windmills and later pumping stations constructed to raise water from the ditches. The story is that we can keep low lying places free of floods if we want to, in spite of gradually rising seas and slightly heavier rainfalls. It requires commitment, good planning and technological solution.

Lewes and Maslin mentioned that ‘We human are not just influencing the present. For the first time in Earth’s 4.5-billion-year history, a single species is increasingly dictating its future. Now there is a new force of nature changing Earth: Homo Sapiens.

Considering the Homo Sapiens and status of the current climate, the Intergovernmental Panel on Climate Change (IPCC) has published a series of three reports, known collectively as the Sixth Assessment Report. These reports are based on the latest findings on the science of climate change, the impacts and adaptation options and the mitigation of climate change. The key messages from the reports are: keeping temperature below two degrees Celsius can only be achieved with immediate actions that lead to deep and rapid cuts in global emissions of greenhouse gases to reach net zero. There is an urgent need to adapt to adverse climate impacts as well as reach net zero.

The UK and some other countries have set a target of net zero greenhouse gas emissions by 2050. However, to reach net zero by 2050 is an arbitrary target. It is not a deadline which, if we fail to meet, will result in the Earth’s ecosystem collapsing and human civilisation with it. But we also know carbon dioxide is accumulating in the atmosphere and global temperature is rising by around 0.1 degree Celsius per decade. It is highly likely that there is a causal link between these two things. Sea levels are rising by around 3 mm a year. This means that some form of its impact on human civilisation such as the collapse of the civilisation cannot be completely ruled out.

However, some prognosis is that it is not practical to achieve net zero by 2050 without causing serious harm to the economy and living standard of the people. When we see a policy document about net zero, we might see the image of wind turbines and solar panels on the cover of the document. This instigates us to believe that this is the way we can achieve net zero, but we are not seriously thinking about carbon-intensive industries such as steel production, which is responsible for between 7-11% of the total greenhouse gas emission.  Also, turbine’s foundation use concrete, the product of cement industry, which account for a further 7% of global emissions. Steel and cement which are needed for wind turbines and solar panel in different forms are responsible for around one in every six tonnes of carbon dioxide emission. It is far from easy to see how either of these industries can be fully decarbonised.

On the other end, we have another scenario, where we can see that dramatic climate change can happen without human factor. For example, research carried out on last ice age in North America by Lora et.al (2016) suggests that it ended over a period of just 100 years- a far more dramatic change than we have seen in the climate over the past century, and all without significant human input. This suggests that either we need to invest in adaptation, employing serious engineering or we need to find some way of transporting people from one place to another. So, adaptation is required anyway even if there is no global warming. This suggests that we need to think more about adaptation of human societies not just because of man-made climate change but because of natural changes in our environment. It is clear that the climate has frequently swung between warm and frozen period in the past, not on time scale of millions of years but often with rapid changes over shorter period.

So, the strategies to achieve net zero greenhouse gases include a range of measures including a shift to low-carbon energy, improved efficiency and reduced demand, and removal of carbon dioxide from the atmosphere. These require consistent policy, infrastructure planning, and research and development in areas including energy storage, renewable energy, agricultural emissions reductions and carbon capture and storage. One should recognise that achieving net zero emission target does not mean zero emission. Also, adaptation should get top priority in the climate strategy because climate can swing from one state to another without any human input.

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The writer is a UK based Academic, Advisor (Science & Environment), Columnist and Author