Past records of ocean acidification - the Palaeogene hyperthermals

自从发现火和发展农业以来，人类一直在向地球大气层释放二氧化碳（CO2）。多年来，我们已经知道燃烧化石燃料和砍伐森林对大气中二氧化碳含量的影响以及对全球气温的影响。然而，我们排放到大气中的二氧化碳并不都停留在那里，因为二氧化碳与水发生反应，目前化石燃料排放的大约三分之一被海洋清除。这种效应将真正有助于我们防止更极端的全球变暖发生，除了...在过去的几年里，科学家们已经意识到，由于二氧化碳溶解在海水中会产生弱酸，我们正在导致海洋的pH值稳步下降，这一过程被称为“海洋酸化”。目前，大气中每百万种气体中约有380个二氧化碳分子（“百万分之一”或ppm）。据预测，大气中的二氧化碳在未来几十年将稳步增加，到2050年将达到450-550 ppm，这是我们的星球至少在过去300万年来从未经历过的浓度。随着大气中二氧化碳的增加，它在海水中溶解的速度也会增加，迫使海洋表面的pH值越来越低。海洋的pH值可能会达到自恐龙时代以来罕见的值。今天生活在海洋中的大多数生物在其进化史上从未经历过如此大的变化。这很重要吗从实验室实验来看，海洋酸化似乎会影响海洋生物，特别是那些用碳酸钙制造外壳和骨骼的生物，因为随着沃茨变酸，碳酸钙矿物质变得不稳定，最终会溶解。如果我们不能控制二氧化碳的排放，使海洋pH值的变化保持在钙化生物未来可以科普的范围内，我们可能会看到它们的外壳溶解，生长缓慢，繁殖失败，侏儒症或活动减少，对生态系统的影响进一步。不受限制的工业活动甚至可能把这些生物推向生态悬崖，造成灭绝。那么未来会发生什么呢？在过去的地质时期，生物通常有数千年到数百万年的时间来适应和进化，以应对全球环境的变化。虽然我们现在造成的全球环境变化快了数百倍，但仍需要几十年的实验室实验来告诉我们海洋生物是否能够适应海洋酸化。当我们知道答案的时候，可能已经太晚了！幸运的是，还有另一条路;一条隐藏在岩石中的路。地质记录，储存在海底的泥浆中，充满了数百万的微化石，记录了生物体可以忍受多少变化，以及多少变化是太多了。我们将采集从海底钻取的古代沉积物样本，使用一系列最先进的技术分析这些样本，包括详细的实验室分析，并应用复杂的计算机模型来帮助完全理解这些数字。这将告诉我们过去海洋的pH值如何变化。通过将这些信息与生态系统变化和物种保护的观察联系起来，将为我们提供重要的线索，如果我们现在不做出更大的努力来减少温室气体排放，我们可能会在未来看到海洋生态系统的变化。

Since the discovery of fire and the development of agriculture, humans have been releasing carbon dioxide (CO2) to the Earth's atmosphere. We have known about the effect that burning of fossil fuels and deforestation has on the amount of CO2 in the atmosphere as well as its influence on global temperatures for many years now. However, the CO2 we put in the atmosphere does not all just stay there / because CO2 reacts with water, about a third of current fossil fuel emissions is removed by the ocean. This effect would be really helpful for us in preventing more extreme global warming from taking place, except ... in past few years scientists have realized that because CO2 dissolved in seawater creates a weak acid, we are causing the pH of the ocean to steadily decrease in a process known as 'ocean acidification'. There are currently about 380 molecules of CO2 in the atmosphere for every million of all gases combined ('parts per million' or ppm). Atmospheric CO2 is predicted to steadily increase in the coming decades, reaching 450-550 ppm by the year 2050 / a concentration that our Planet has not experienced in at least the past 3 million years. As atmospheric CO2 increases, so does the rate at which it will dissolve in seawater, forcing the pH of the surface ocean lower and lower. It is likely that ocean pH will reach values seen only rarely since the time of the Dinosaurs. Most organisms alive in the ocean today have never experienced such a large change in all their evolutionary history. Is this important? From laboratory experiments it seems that ocean acidification will affect marine organisms, particularly those that make shells and skeletons out of calcium carbonate, because calcium carbonate minerals become less stable as waters become more acidic and will eventually dissolve. If we fail to control CO2 emissions to keep ocean pH change within the limits calcifying organisms can cope with in the future, we may see dissolution of their shells, slower growth, failure to reproduce, dwarfism, or reduced activity, with impacts further the ecosystem. Unrestricted industrial activities may even push these organisms over an ecological precipice and cause extinctions. So what is going to happen in the future? In the geological past, organisms normally had thousands to millions of years to adapt and evolve in response to global environmental change. Although the global environmental change we are causing now is many hundreds of times faster, it would still take laboratory experiments conducted over decades to tell us whether marine organisms will be able to adapt to ocean acidification. By the time we know the answer, it may be too late! Luckily, there is an alternative path; one that lies hidden in rocks. The geological record, stored in the mud at the bottom of the ocean is packed with millions of microfossils that record how much change organisms can tolerate and how much is too much. We will take samples of ancient sediments that have been drilled from the ocean floor, analyse these samples using a range of state-of-the-art techniques involving detailed laboratory analyses, and apply complex computer models to help make complete sense of the numbers. This will tell us how the pH of the ocean changed in the past. By linking this information with observations of ecosystem changes and species extinctions will provide vital clues to what changes in marine ecosystems we might expect in the future if we do not make much greater efforts to curtail our greenhouse gas emissions now.