Why accurate measurement is essential for effective climate action

Anyone who has been to climate change or sustainability conferences during the last decade will have heard the words 'you can't manage what you don't measure' so often that they now develop a rash whenever they are uttered.

But whilst both dull and overused, the phrase is also true. Without accurate baselines, it is impossible for countries to set their emissions reduction targets, and even harder to negotiate a convincing position in the global climate change talks.

We all know that the UK is a leader in both setting scientifically appropriate climate targets and negotiating for more climate action globally. The Committee on Climate Change, shortly due to publish its fifth carbon budget for the years 2028 -2032, advises Parliament on progress towards and how to meet the 2050 goal to reduce the UK’s emissions by 80%. Successive UK governments have played a strong role in global climate negotiations and will need to do so again at the United Nations Conference on climate change (COP21) in December in Paris to help secure an effective deal.

But all of this depends on the UK’s ability to monitor progress, and that in turn depends on accurate measurement of greenhouse gas emissions (GHGs). What many people don’t know is that the UK is leading in this area too.

Most people will be familiar with the concept of a carbon footprint. To figure out yours, take your activities that emit greenhouse gases, such as driving 300 miles a month, producing a bin bag of waste every week, and using 4000 kWh of electricity, and multiply these by ‘emissions factors’ – multipliers that turn your activity data into a carbon footprint.

Fewer people will have stopped to wonder where these emissions factors come from. How on earth does anyone know, for example, that disposing of one tonne of waste to landfill results in 290 kilograms of carbon dioxide equivalent emissions?

In this case, the answer is that the UK’s National Physical Laboratory (NPL) has visited landfill sites and measured the methane emissions coming from them with our mobile emissions monitoring facility, DIAL. Combined with data about the sites measured – the amount of waste stored in them, their age, and so on – these measurements can be used to produce the emissions factor for waste to landfill. As it’s very difficult for people to be sure about the amount of waste they use (I certainly don’t weigh my bin bags…) the more accurate we can make the emissions factor, the more reliable carbon footprint estimates will be, both for individuals and for the nation.

Equipment like DIAL can be deployed not only to measure baseline emissions, provide emissions factors, and monitor progress against targets but also helps to determine the necessary steps to mitigate emissions. Taking the contentious issue of shale gas extraction for example, monitoring equipment will not only detect if there is a leak and quantify it, but will also ensure the operator is able to identify where it is coming from and fix it.

Measurements can also provide a check on what the calculations are telling us. A network of global monitoring stations informs us about the concentrations of GHGs in the atmosphere at specific locations. When the media reported that levels of carbon dioxide in the atmosphere had exceeded 400 parts per million for the first time in May 2013, the data was taken from a station in Hawaii that has been measuring carbon dioxide levels since 1958. The UK has a number of stations that operate in the same way, including one operated by NPL at the Divis station in Northern Ireland.

Finally and critically, measurements can be used to check climate models. The proposed TRUTHS’ satellite mission, for example, will improve measurements of incoming and reflected solar radiation tenfold. These measurements can be compared to what the climate models are predicting, helping to show which models are predicting particular climate variables correctly and enabling a sound evidence base for policy-makers.

As the urgency to mitigate climate change grows, so does our ability to detect and quantify GHGs. We need these measurements to determine the scale of the challenge, set emissions reduction targets and monitor our progress against them. We need them to provide a firm foundation for policy decisions, and to understand the impact of these policies. Ultimately, the rest of the world needs accurate measurements so countries can support meaningful agreements at international negotiations such as the upcoming COP21 in Paris.

This blog was written by Jane Burston, Head of Climate and Environment at the National Physical Laboratory.

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