Review: The Science of Climate Change

Review: The Science of Climate Change

How is human activity affecting natural climate change and what do current trends tell us?

Dr Andrew Haggart spoke to us eloquently about the basis of the scientific research on climatic change.  He described data that provides evidence about natural climatic variation and also about man’s impact on climatic warming.

Dr Haggart is Principal Lecturer in Geography and Environmental Science at the University of Greenwich and, in particular, is an expert in Holocene land and sea-level changes in south-east England. His research is concerned with reconstructing environmental history and charting early human alteration of the environment.

Dr Haggart took us on a journey back though history. Firstly reviewing recorded weather information for the recent past, showing volatility in local climate but not climatic warming (which takes place over much longer time periods). As we traveled further back in time looking at data gathered from ice cores we saw how there have been multiple climatic changes, both global warming and cooling.  Geophysical data climate scientists have been able to accurately model the historical natural changes in climate from this information. It is clear that the time scales involved are difficult for humans to intuitively grasp as they measure millennia.

Multiple groups of climate scientists have interrogated the climate change data from prehistory and modeled it to predict recorded measures of temperature in the modern era. They check this against other data sources and find that the models are able to predict the warming that is occurring due to the long term natural cycling of climate. However, in the very recent time period since the industrial revolution, particularly since the 1950’s, the multiple models do not explain the recent steep rise in global average temperatures. This recent variation can be explained only through adding to the models the man-made increases in greenhouse gas emissions (methane and carbon dioxide). It is clear that human activity has unbalanced the natural climatic cycle leading to this recent warming. This warming will be detrimental to humans across the globe both because of its direct and indirect effects.

We viewed the climate heat maps that showed the predicted future average temperatures across parts of the globe and in the UK specifically, according to the level of warming we can expect due to man-made contributions. These were organized by the extent of the average rise in temperatures. There are areas of the globe that are climatically more vulnerable than others and will be devastatingly affected by climatic warming, probably within an average lifespan and some that are already feeling the effects now. The UK does not appear to be as directly vulnerable as other areas of the planet but will feel the knock on effect of disruption and instability caused by water shortages and loss of agricultural land in other parts of the globe.

There were some pertinent questions during the Q&A and Dr Haggart was able to show us maps of how the UK may be affected by rising sea levels. Of local concern the Thames barrier is likely to be sufficient until around 2080, however a number of the major cities of the world are close to the sea and will be affected in the future if warming continues even along the most conservative estimates (under 2 degrees centigrade).  Eating meat was mentioned as a contributing factor and we learned in the discussion that around a third of GHG emissions are as a result of the food system activity. Perhaps eating less meat and reducing food waste are practical measures we could make ourselves to reduce the impact of our activity on the planet.

Further reading:

A good source of information, presenting evidence for man-made contributions to climate change, is here.

An article in the Independent about reduction in meat consumption and climate change is here.

An in depth study was published by Oxford University that looks at the type of meat consumption switching that would have greatest impact is here.