Sir David King at Green Monday

The second keynote at this month's Green Monday provided much food for thought. Sir David King agreed with Jon Williams that population growth is a key challenge, fuelled by life expectancy increasing from 45 to nearly 80. Not only that but urbanisation means that these people will have increasingly higher aspirations, and that has to be balanced against the need to reduce greenhouse gas emissions. An 80% reduction is needed on average, so the change must be transformational, not incremental.

Energy is seen as a basic freedom but decarbonisation of the economy is essential, and necessity is the mother of invention. We will find ways but it will proably be the private sector that seizes the opportunity. As an example, if we only converted one 10,000th of the sun’s energy to power we would have enough to sustain a population of 9billion.

If we fail to accept the challenge of decarbonisation, the great powers will battle for resources. Sir David King considers that the Iraq war may have been the first example of this. The cost of that conflict is estimated at $3 trillion. It’s estimated that the global emissions trading scheme which emerged from Kyoto will be worth $1 trillion when it first goes global. If the US government had invested in finding alternative energy sources rather than going to war over oil, then we could be in a very different place now.

We need visionary leadership from the great powers, and we need them to mainstream climate issues. It's not about making freestanding speeches about climate change, but making climate part of every speech as a key part of government strategy.

Prof. John Beddington at Green Monday

I spent a most enjoyable evening at Green Monday, the monthly networking event organised by the 2degrees network and Green Business Events. Keynote speaker was Professor John Beddington, the goverment's Chief Scientific Advisor. Surprisingly, he talked less about green issues than about urbanisation and food security, although it soon became clear that these issues are closely connected with climate crisis.

Currently, 47% of the World's population lives in an urban environment, and this is expected to increase to 60% by 2030. Meanwhile, the population is increasing by 6 million people per month and migration from rural to urban areas is increasing fastest in the developing world (in fact, migration from urban to rural is the rule in many developed countries). This is partly driven by changing rainfall patterns, which have caused a 20% reduction in agricultural output according to the Hadley Centre.

Efforts to alleviate global poverty are working - which is, of course, a good thing. But there's a trade-off. The World Bank calculated that in 2005 250 million households had an income greater than the equivalent of £8,000 sterling per annum - not a massive amount but well above the poverty line in most developing countries. It predicts that the number in this income bracket will be 2 billion households by 2050. And as these people acquire more disposable income, they will increase demand for certain products.

So what does all this mean? Well, the arrival in the cities of these newly affluent individuals will put increasing pressure on the food and water supply. Water is currently a free good in these areas, but increasing scarcity and demand will make it a tradable commodity and cities will compete against farmers - and the wealthier cities are likely to win. Without sufficient water for irrigation, food production will be compromised in currently fertile areas, accelerating the rate of decline in food production. Demand for food is expected to increase by 50% over the next 20 years; the conflict is clear.

Climate crisis is now a widely accepted phenomenon and the debate has moved on from whether or not it exists to what we should do about it. But even if we fail to prevent global warming, the full consequences could take decades to manifest themselves. Meanwhile, subtle changes in the weather pattern are being exacerbated by urbanisation to create food security issues which are already being felt and which will become critical within our lifetime.