[{"command":"openDialog","selector":"#drupal-modal","settings":null,"data":"\u003Cdiv id=\u0022republish_modal_form\u0022\u003E\u003Cform class=\u0022modal-form-example-modal-form ecl-form\u0022 data-drupal-selector=\u0022modal-form-example-modal-form\u0022 action=\u0022\/en\/article\/modal\/7198\u0022 method=\u0022post\u0022 id=\u0022modal-form-example-modal-form\u0022 accept-charset=\u0022UTF-8\u0022\u003E\u003Cp\u003EHorizon articles can be republished for free under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.\u003C\/p\u003E\n \u003Cp\u003EYou must give appropriate credit. We ask you to do this by:\u003Cbr \/\u003E\n 1) Using the original journalist\u0027s byline\u003Cbr \/\u003E\n 2) Linking back to our original story\u003Cbr \/\u003E\n 3) Using the following text in the footer: This article was originally published in \u003Ca href=\u0027#\u0027\u003EHorizon, the EU Research and Innovation magazine\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003ESee our full republication guidelines \u003Ca href=\u0027\/horizon-magazine\/republish-our-stories\u0027\u003Ehere\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003EHTML for this article, including the attribution and page view counter, is below:\u003C\/p\u003E\u003Cdiv class=\u0022js-form-item form-item js-form-type-textarea form-item-body-content js-form-item-body-content ecl-form-group ecl-form-group--text-area form-no-label ecl-u-mv-m\u0022\u003E\n \n\u003Cdiv\u003E\n \u003Ctextarea data-drupal-selector=\u0022edit-body-content\u0022 aria-describedby=\u0022edit-body-content--description\u0022 id=\u0022edit-body-content\u0022 name=\u0022body_content\u0022 rows=\u00225\u0022 cols=\u002260\u0022 class=\u0022form-textarea ecl-text-area\u0022\u003E\u003Ch2\u003EA 40-million-year-old layer of dust can help predict how monsoons will change\u003C\/h2\u003E\u003Cp\u003EThe dust blew in some 40 million years ago, originating from the same places that the winter monsoons bring dust from today. There is none to be found before this date \u2013 but dust has been deposited ever since.\u003C\/p\u003E\u003Cp\u003EMonsoons provide water for half the world\u2019s population and occur throughout the tropics and sub-tropics, though the most powerful is the South Asian monsoon. As the summer heat grows, cool, moisture-laden air wafts in from the ocean, warms and rises, releasing its load when it reaches the cooler temperatures above. In the winter, the opposite happens with glacial winds blazing from the Arctic and blowing dust all over Asia and surrounding oceans.\u003C\/p\u003E\u003Cp\u003EBut monsoons are still poorly understood, and today\u2019s climate models disagree about how increased carbon dioxide (CO\u003Csub\u003E2\u003C\/sub\u003E) in the atmosphere will alter them. By understanding how monsoons started, and how this weather phenomenon and CO\u003Csub\u003E2\u0026nbsp;\u003C\/sub\u003Erelate to each other, researchers can improve today\u2019s models.\u003C\/p\u003E\u003Cp\u003EScientists had thought the Asian monsoon began about 25 million years ago, but recently several independent teams \u003Ca href=\u0022https:\/\/www.nature.com\/articles\/nature13704 \u0022\u003Epublished evidence pushing back the date\u003C\/a\u003E to around 40 million years ago. It was around this time that the two continents of India and Asia collided, pushing the Himalayas and the Tibetan plateau into existence, and, sometime between 55 and 34 million years ago, Earth began cooling from a warm, ice-free planet to the bi-polar icehouse conditions of today. Professor Guillaume Dupont-Nivet, a specialist in palaeoenvironment at the French National Centre for Scientific Research (CNRS) in Paris, thinks that monsoons may have had a pivotal part to play in this cooling.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECooled\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EHe thinks that vigorous rains caused huge wearing-away of the mountains, known as weathering. Weathering is known to draw CO\u003Csub\u003E2\u0026nbsp;\u003C\/sub\u003Efrom the atmosphere in a number of ways \u2013 for example, the resultant dust, when it reaches the sea, feeds plankton which then absorb CO\u003Csub\u003E2\u0026nbsp;\u003C\/sub\u003Eas they grow. With less CO\u003Csub\u003E2\u0026nbsp;\u003C\/sub\u003Eto insulate the atmosphere, the greenhouse effect weakened and the climate cooled.\u003C\/p\u003E\u003Cp\u003E\u2018There are many theories about the global cooling and that\u2019s only one of them,\u2019 said Prof. Dupont-Nivet.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003ETo test his theory, his team has been hunting for traces of the first monsoons, in a project called \u003Ca href=\u0022https:\/\/cordis.europa.eu\/project\/id\/649081\/fr\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003EMAGIC\u003C\/a\u003E.\u003C\/p\u003E\u003Cp\u003EBut looking for evidence of yearly weather events that happened tens of millions of years ago is a difficult task.\u003C\/p\u003E\u003Cp\u003EThe team examined rock in three areas \u2013 Myanmar, Tajikistan and northeast Tibet.\u003C\/p\u003E\u003Cp\u003EThey found fossilised pollen grains from which they determined the species of plant that were there. They have tracked them evolving to cope with the change of climate and then disappearing when deserts took over. Knowing the conditions under which different species thrive, they were able to deduce the humidity and temperature in successive seasons.\u003C\/p\u003E\u003Cp\u003EThe scientists also used isotope analysis of leaf wax \u2013 a tough substance that survives millions of years after the plants that secreted them have degraded. In nature, some elements occur in several forms that differ only in mass \u2013 for example there are two common isotopes of oxygen \u2013 oxygen 16 and oxygen 18 \u2013 and of hydrogen. How much of each isotope is preserved in the fossil depends on the temperature and humidity at which it thrived. This means that, when plants absorb water, it leaves a fingerprint in their tissues that hints at the climate conditions.\u003C\/p\u003E\u003Cp\u003E\u2018These are difficult questions when you are looking 40 million years in the past but when we combine these proxies we are able to \u2026 tell how temperature and rainfall changed with the seasons,\u2019 said Prof. Dupont-Nivet.\u003C\/p\u003E\u003Cp\u003EIn Myanmar, the weather did vary seasonally in the typical way of monsoons, though Prof. Dupont-Nivet says that other explanations also fit the data.\u003C\/p\u003E\u003Cp\u003EBut the \u003Ca href=\u0022https:\/\/meetingorganizer.copernicus.org\/EGU2019\/EGU2019-16217.pdf\u0022\u003Edust in Tibet\u003C\/a\u003E \u2018is a major discovery,\u2019 he says.\u003C\/p\u003E\u003Cp\u003E\u2018What is very exciting is that we record the onset \u2026 There is no dust for tens of millions of years and then the beginning of it, and then there is dust until today.\u2019\u003C\/p\u003E\u003Cp\u003EThe team realised that the arrival of the dust coincided precisely with the disappearance of a huge sea that used to cover Eurasia from China to Europe. When India collided with Asia this water was cut off from the ocean and gradually evaporated, leaving behind deserts and the isolated Aral, Caspian and Black seas. Analysis of the dust revealed that it had come from this area which shows that these events changed the way air circulated, driving the first dust from these deserts towards regions like Tibet, he says.\u003C\/p\u003E\u003Cp\u003EWhat began 40 million years ago was a weaker proto-monsoon of what we have today, according to Prof. Dupont-Nivet.\u003C\/p\u003E\u003Cp\u003E\u2018It\u2019s very close (to today\u2019s monsoon) because we get strong winds that carry this dust and the dust has a lot of impact on the climate,\u2019 he said. \u2018It could be responsible for some of the cooling.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022tw-text-center tw-text-blue tw-font-bold tw-text-2xl lg:tw-w-1\/2 tw-border-2 tw-border-blue tw-p-12 tw-my-8 lg:tw-m-12 lg:tw--ml-16 tw-float-left\u0022\u003E\n \u003Cspan class=\u0022tw-text-5xl tw-rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n \u003Cp class=\u0022tw-font-serif tw-italic\u0022\u003E\u2018Over the last decade or so there\u2019s been a lot of time and money put into developing these climate models \u2026 but the uncertainty in monsoon predictions has not gone down.\u2019\u003C\/p\u003E\n \u003Cfooter\u003E\n \u003Ccite class=\u0022tw-not-italic tw-font-normal tw-text-sm tw-text-black\u0022\u003EDr Michael Byrne, Universities of Oxford and St Andrews, UK\u003C\/cite\u003E\n \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EFuture\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EThe data will help test the predictions climate models make for the monsoons of the future, he says.\u003C\/p\u003E\u003Cp\u003EToday\u2019s big climate models cannot agree on whether climate change will cause monsoons to strengthen or weaken, or whether their time of onset will change, says Dr Michael Byrne, climate scientist at the Universities of Oxford and St Andrews in the UK.\u003C\/p\u003E\u003Cp\u003EAll the climate models agree that global warming is packing more water vapour into the air which should cause a wetter monsoon. Some also suggest that, in South Asia, black carbon and sulphate pollution have recently weakened it.\u003C\/p\u003E\u003Cp\u003EBut they don\u2019t agree on the influence of CO\u003Csub\u003E2\u0026nbsp;\u003C\/sub\u003Eon more complicated factors, such as cloud size, wind direction and the rate at which moisture-laden air from the sea rises.\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u2018Over the last decade or so there\u2019s been a lot of time and money put into developing these climate models so they can simulate every part of the world in (increasingly) higher resolution \u2026 but the uncertainty in monsoon predictions has not gone down,\u2019 said Dr Byrne.\u003C\/p\u003E\u003Cp\u003EAs a result, it\u2019s not clear whether monsoons will begin earlier or later than they do today, for example.\u003C\/p\u003E\u003Cp\u003EHe has therefore taken a radical approach for his project, MONSOON. Instead of adding more complexity, he went back to the basics, depicting just a few of the fundamental forces shaping monsoons.\u003C\/p\u003E\u003Cp\u003EIn fact, he has dispensed with land altogether and has built an \u2018aquaplanet\u2019. Without land to complicate matters, he can focus on clouds, CO\u003Csub\u003E2\u0026nbsp;\u003C\/sub\u003Eand water vapour cycles.\u003C\/p\u003E\u003Cp\u003E\u2018The headline result is that clouds and water vapour (by absorbing and reflecting energy emitted by the sun and Earth) have a very strong influence on the monsoon,\u2019 he said. Increased CO\u003Csub\u003E2\u0026nbsp;\u003C\/sub\u003Eincreases the amount of water vapour which \u2018tends to make the monsoon stronger and wetter\u2019.\u003C\/p\u003E\u003Cp\u003E\u2018But it has some other interesting effects which are less obvious. When you switch on this water vapour effect you tend to delay the monsoon onset by about ten days, which is not well known.\u2019\u003C\/p\u003E\u003Cp\u003EThese simulations show that these are important monsoon processes that to date have been almost entirely neglected, he says. \u2018(And they) have great potential to possibly explain some of the large uncertainty we see in the state-of-the-art climate model projections.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThe research in this article was funded by the EU.\u003C\/em\u003E\u003C\/p\u003E\u003C\/textarea\u003E\n\u003C\/div\u003E\n\n \u003Cdiv id=\u0022edit-body-content--description\u0022 class=\u0022ecl-help-block description\u0022\u003E\n Please copy the above code and embed it onto your website to republish.\n \u003C\/div\u003E\n \u003C\/div\u003E\n\u003Cinput autocomplete=\u0022off\u0022 data-drupal-selector=\u0022form-ms4cao72kj-w4ol4mwullnaxy4vfcyxxhe1woqoq-us\u0022 type=\u0022hidden\u0022 name=\u0022form_build_id\u0022 value=\u0022form-ms4CAO72Kj-W4oL4mwUlLNaxy4vfCyxxHE1woQOq_us\u0022 \/\u003E\n\u003Cinput data-drupal-selector=\u0022edit-modal-form-example-modal-form\u0022 type=\u0022hidden\u0022 name=\u0022form_id\u0022 value=\u0022modal_form_example_modal_form\u0022 \/\u003E\n\u003C\/form\u003E\n\u003C\/div\u003E","dialogOptions":{"width":"800","modal":true,"title":"Republish this content"}}]