Novel constraints on sources and sinks of methane and carbon monoxide from measurements and modelling of radiocarbon

我们如何通过测量大气来了解导致气候变化和空气污染的排放？在这个项目中，我们将使用一种强大的新测量技术来测量来自不同来源的甲烷和一氧化碳的排放量。甲烷是气候变化的第二大原因。它的产生有很多来源，包括垃圾填埋场、牲畜和天然气泄漏，但它的排放并不广为人知。一氧化碳造成空气污染，其来源包括汽车燃烧汽油和家庭取暖燃烧木材。为了应对气候变化和空气污染的威胁，英国政府和世界各地的其他政府正在实施减少人类活动排放的政策。例如，在英国，在过去的几十年里，垃圾填埋场的甲烷排放量减少了，因为从垃圾填埋场捕获甲烷气体的新技术已经引入并随着时间的推移而改进。为了计算垃圾填埋场的排放量，政府考虑了每个垃圾填埋场的规模和管理甲烷排放的做法。类似的会计计算也适用于其他类型的排放。测量大气中甲烷和一氧化碳的放射性碳含量，检验排放计算的准确性。放射性碳是一种随着时间的推移而衰变的碳，它通常用于估计考古学中材料的年龄。因为化石燃料太老了，它们所有的放射性碳都已经衰变了。因此，天然气泄漏或汽油燃烧等化石燃料的排放将降低甲烷或一氧化碳中放射性碳与其他类型碳的比例。牲畜或垃圾填埋场产生的甲烷，以及燃烧生物燃料产生的一氧化碳都含有放射性碳，因为放射性碳是在大气中产生的。我们开发了一种新系统，可以比以往任何时候都更有效地测量放射性碳。我们将在伦敦和大西洋的观测点应用新系统来测量大气中甲烷和一氧化碳中的放射性碳。通过这些测量，我们将能够知道伦敦和英格兰东南部有多少甲烷和一氧化碳排放来自化石燃料或其他来源。这将使我们能够评估英国报告的排放量，并更好地了解需要做出哪些改变来减少总体排放量。我们将利用大西洋的测量数据来研究全球不同来源的排放，以及破坏大气中甲烷和一氧化碳的化学反应如何随时间变化。我们将使用计算机模拟大气，计算出排放物是如何移动的，以及破坏甲烷和一氧化碳的化学反应在何时何地最强烈。通过将我们的测量结果与计算机模拟结果进行比较，我们可以确定在报告的排放或计算机模拟中的化学反应中可能存在的错误。该项目将对全球和英国的化石燃料对甲烷和一氧化碳排放的贡献进行独特的评估。我们将量化破坏甲烷和一氧化碳的化学反应每年变化的程度，这对于避免将这些化学反应的变化误认为人类排放的变化至关重要。通过这项关于甲烷和一氧化碳排放的独特新研究，我们将帮助提高正在实施的应对气候变化和空气污染的政策的有效性。

How can we learn about the emissions contributing to climate change and air pollution by making measurements of the atmosphere? In this project, we will measure the emissions of methane and carbon monoxide from different sources using a powerful new measurement technique. Methane is the 2nd biggest cause of climate change. It is produced by many sources including landfills, livestock and natural gas leaks, but its emissions are not very well-known. Carbon monoxide contributes to air pollution and its sources include the burning of petrol in motor vehicles and the burning of wood for home heating.To address the threats of climate change and air pollution, the UK government and other governments around the world are implementing policies to reduce emissions from human activities. For example, in the UK, methane emissions from landfills decreased over the past few decades because new technologies to capture methane gas from landfills have been introduced and improved over time. To calculate landfill emissions, the government takes accounts of each landfill's size and practices for managing methane emissions. Similar accounting calculations are performed for other types of emissions. We will measure the amount of radiocarbon in atmospheric methane and carbon monoxide to check the accuracy of these emissions calculations. Radiocarbon is a type of carbon that decays over time, and it is commonly used for estimating the age of materials in archaeology. Because fossil fuels are so old, all of their radiocarbon has decayed away. Therefore, emissions from fossil fuels such as natural gas leaks or petrol combustion will decrease the ratio of radiocarbon to other types of carbon in methane or carbon monoxide. Methane from livestock or landfills, and carbon monoxide produced by biofuel burning, contain radiocarbon because radiocarbon is produced in the atmosphere.We have developed a new system to make measurements of radiocarbon more efficiently than ever before. We will apply the new system at observation sites in London and in the Atlantic Ocean to measure radiocarbon in atmospheric methane and carbon monoxide. With these measurements, we will be able to tell how much of the methane and carbon monoxide emissions in London and southeast England are coming from fossil fuels or from other sources. This will allow us to evaluate the UK's reported emissions and understand better what changes need to be made to reduce overall emissions. We will use the measurements in the Atlantic Ocean to study emissions from different sources across the entire globe, and how chemical reactions that destroy methane and carbon monoxide in the atmosphere vary over time. We will use computer simulations of the atmosphere that calculate how emissions move around and where and when the chemical reactions destroying methane and carbon monoxide are the strongest. By comparing our measurements to the computer simulations, we can determine where there may be errors in the reported emissions or in the chemical reactions included in the computer simulations.This project will provide a unique evaluation of the fossil fuel contribution to methane and carbon monoxide emissions, both globally and in the UK. We will quantify how much the chemical reactions destroying methane and carbon monoxide change year-to-year, which is crucial for avoiding mistaking changes in these chemical reactions for changes in human emissions. With this unique new study on methane and carbon monoxide emissions, we will help to improve the effectiveness of policies being implemented to address climate change and air pollution.