What the UAE's geological mysteries teach us about climate change

Global environmental change is an increasing concern, particularly in the Gulf. Extreme weather events and rising temperatures and sea levels are becoming more evident by the year. As the climate in the UAE is already hot and dry, and most of its population concentrated along the coastline, what will the future hold? Today, this vital question is typically investigated with complex climate models, and the underlying science is regularly assessed by the UN’s Intergovernmental Panel on Climate Change (IPCC), which summarises its findings in periodical reports. Its most recent one concluded that climate change is rapid and intensifying. Fortunately, and unbeknown to many, billions of years of geological history can help help us understand the nature of today’s challenge and help us predict our collective future. The ground under the UAE has much to offer in this endeavour. Its heritage extends back into “deep time", hundreds of millions of years into the past. This is far beyond the hundreds of thousands of years when the region is first thought to have been inhabited by humans. In deep geological terms, several mass extinction events have now been recognised, each of them wiping out more than 70 per cent of species at the time. To understand the causes and effects of these disasters, we need to try our best to read the diverse sedimentary rocks found in the UAE, a form of natural archive. Consider the mountain ranges of the northern emirates and Jebel Hafeet near Al Ain as books waiting to be read. The first challenge is to understand the language of these books, in order to be able to read them. Then we need to identify the “pages” that contain information about previous catastrophes. This is extremely difficult. Just imagine sifting through millions of pages to find only one containing the information we need. It is not an easy task, but reading earth’s history is a vocation we geologists train for and happily spend much of our lives doing. Scientists from UAE universities have published their findings on the region for decades. But our area of research has gathered significant momentum recently, as the effects of climate change on biodiversity, sea levels and coastal cities and infrastructure move into public interest. Now, earth scientists of various backgrounds are flocking to the region to contribute to research taking place at the UAE’s exquisite geological “archives". Recognising the importance of climate change science, the UAE established the Ministry of Climate Change and the Environment, which now gathers local expertise through the UAE Climate Change Research Network. It is well established that most environmental crises, particularly a number of huge extinction events that took place around 200 million years ago, were triggered by a significant increase in atmospheric CO2 levels, resulting in global warming, changes in sea levels and other terrifying marine issues such as ocean acidification and low oxygen levels in seawater. Does this sound familiar? These shifts are very similar to the ones we are concerned about today. There is major difference, however. Millions of years ago, gasses from volcanoes were to blame. Today, we are. Another important distinction is the timescales involved. While former, “natural” volcanic episodes lasted for tens to hundreds of thousands of years, similar amounts of greenhouse gasses are nowadays emitted over much shorter periods of time, basically starting when the industrial revolution began just 200 years ago. Time matters, and yet it is hard for us humans, particularly non-specialists, to grasp quite how short 10,000 years is in geological terms, let alone 200. The UAE’s coastline can give us an idea, however. In just 20,000 years, well within the period of human inhabitation, there have been dramatic changes in sea levels. Initially, during the last ice age, the ocean was 120 metres lower than it is today, due to so much water being held in thick polar ice caps. The Arabian Gulf was dry at that time, and was the source of calcareous dust that accumulated in now-fossilised dunes, the remnants of which are abundant in coastal areas of Abu Dhabi. With the subsequent melting of the polar ice caps, sea levels rose rapidly, flooding the Arabian Gulf, very likely displacing humans that might have lived there. This might even have been the same event that is referred to as Noah’s flood in the Book of Genesis, a shared narrative among the Abrahamic faiths. The rises were so great that the coastline around Abu Dhabi today was two metres underwater 6,000 to 4,000 years ago. The most spectacular evidence for this is a huge fossilised skeleton of a humpback whale that became stranded at the time, which was eventually dug up in today’s Mussafah district in Abu Dhabi, several kilometres inland from the city’s shoreline. These sea level changes and the rocks they left behind show how the UAE was the site of very real transition from "deep time” to a period when humans were perhaps living through the catastrophic trauma brought on by climate change. And yet, remarkably little is known about the exact timing and extent of these comparatively recent sea level changes in the UAE. As mentioned earlier, a considerable degree of skill and effort is required to be able to read the rocks of this country, be they in mountains, on coastlines or even in petroleum basins. Fortunately, there is an increasing number of students interested in these beyond-ancient issues, which today are surprisingly timely. New undergraduate and graduate degree programmes are springing up for aspiring geologists, which now go beyond the traditional preference for teaching students solely about petroleum engineering. In addition to improving education on the UAE’s priceless geological sites, we must also double up on protection. The recent, and rare, vandalism of outcrops of fossils dunes at Al Wathba near Abu Dhabi shows that a minority are not aware of the preciousness of this aspect of the country’s heritage. Unlike books, rocks cannot be digitised to preserve their content, which is why current generations must safeguard them so that students of the future can carry on pushing the boundaries of the field. There are so many reasons to be motivated in this important task. We are seeing continuing improvements in geochemical, geophysical and other analytical technologies, all of which help geoscientists extract the information they need. An increasingly multidisciplinary group of experts are entering the natural library of our geological and prehistorical past. And they are finding more and more evidence and information that will help us in what could be an existential struggle up ahead.