The British are often said to have an obsession with the weather. This is perhaps unsurprising when the weather can have a considerable impact on our day-to-day lives. For the people of the south west the impact of recent weather has been devastating and it will take many months to count the costs and repair the damage caused by this winter’s floods and storms.
I am in Bristol this week talking about the science underpinning our understanding of climate change, and the options for responding. Whether to expect more of this kind of ‘extreme’ weather as a result of man-made climate change is 1 of the most topical questions in this important global debate.
There is a crucial distinction between the weather we experience on an hourly or daily basis, and climate, which is the average weather over a period of time. Our climates are changing, and greenhouse gas emissions from human activities are in large part responsible. The scientific consensus on this is very clear. There is ample evidence, from multiple sources: the atmosphere is warming, the oceans are warming, glaciers and ice sheets are melting and sea levels are rising. There is also strengthening evidence that some types of extreme weather events are increasing in frequency and intensity.
Can recent extreme weather in the UK be linked to climate change? The answer isn’t simple. Because floods and storms occur naturally as part of the UK’s normal weather, scientists cannot definitively say that any 1 extreme weather event has been directly caused by the extra greenhouse gases emitted through human activities. But scientists’ general expectation is that more greenhouse gases in the atmosphere will lead to more extreme events.
Research from the Met Office, the leading experts in public weather services and climate change, indicates that while we may not be seeing more rainfall across the UK overall, heavy downpours may be becoming more intense. High intensity rainbursts are more difficult for our natural and built infrastructure to cope with, and so bring an increased risk of flooding.
We need to understand the risks of climate change to be able to debate the options for responding. As with any prediction, there are uncertainties in scientists’ ability to predict future risk and impacts of climate change. However, uncertainties are not cause for inaction. Waiting to see how much worse it gets before action is taken is not an option.
Climate change is not reversible on short timescales. The carbon dioxide we emit can stay in the atmosphere for up to hundreds of years, continuing to warm the climate. So, even if emissions stopped tomorrow the climate would continue to warm for several more decades regardless and sea levels would rise for centuries to come. Every year emissions continue to rise we add to the level of warming that becomes inescapable, and to the level of risk we impose on future generations.
If we are to limit the risks from global warming we need to reduce emissions of greenhouse gases from fossil fuels. The challenge is to ensure at the same time a secure energy supply that is affordable.
A mix of energy technologies is likely to be needed to achieve this, including renewable technologies (like wind and solar power), nuclear energy, and transition technologies, like carbon capture and storage, which would allow us to continue to use fossil fuels in a way that is less damaging to the environment. The recent agreement to construct Hinkley Point C nuclear power station is an important part of our low carbon energy future.
As well as reducing our emissions we must adapt to those impacts which we are already committed to. Resilience to the impacts of climate change needs to be built in to decision-making. We need to ensure that our infrastructure - including buildings, transport, energy and agricultural systems - are designed to withstand future climatic conditions.
Bristol is a shining example of the impact that positive local action can have - both directly, and indirectly through inspiring others. With the lowest per capita emissions for any major city in the UK and home to 1 of the UK’s largest green business clusters, the award of European Green Capital for 2015 is well deserved.
Bristol is also 1 of the first cities to be invited to join the Rockefeller Foundation’s new global network of 100 Resilient Cities, an initiative aimed at embedding resilience into urban planning, helping to ensure preparedness for the challenges of the future.