0:00:04 > 0:00:08Dust storms are a scourge of modern life in much of the world.
0:00:08 > 0:00:11In order to produce a dust storm
0:00:11 > 0:00:15you need wind and you need soil particles.
0:00:15 > 0:00:16Get off the road!
0:00:16 > 0:00:19We look at what a dust storm is.
0:00:19 > 0:00:23The dust storm is actually when the visibility is less than a kilometre.
0:00:24 > 0:00:27And how human activity is making them worse.
0:00:29 > 0:00:30We focus on the Middle East...
0:00:30 > 0:00:32About to be engulfed!
0:00:32 > 0:00:34..one of the world's worst-hit areas.
0:00:36 > 0:00:38During the dust-storm season,
0:00:38 > 0:00:41patients get severe attacks of asthma
0:00:41 > 0:00:45that require hospital admission and intensive care.
0:00:46 > 0:00:49We'll see how NASA's satellites can track dust storms
0:00:49 > 0:00:51as they sweep across the Earth.
0:00:52 > 0:00:55The dust can be lifted up to three or four miles in altitude
0:00:55 > 0:00:59before it's really, kind of, carried away by the winds.
0:01:00 > 0:01:03Every year, the current estimate is anywhere
0:01:03 > 0:01:06from two to five billion metric tonnes.
0:01:06 > 0:01:09It moves around some distance in the Earth's atmosphere every year.
0:01:09 > 0:01:12So it's quite a bit of dust.
0:01:13 > 0:01:15Dust isn't always bad.
0:01:15 > 0:01:17Scientists are researching the impact of dust
0:01:17 > 0:01:20crossing the ocean from Africa to Florida.
0:01:20 > 0:01:23I think the fact that we can see these impacts so far away
0:01:23 > 0:01:25is really exciting.
0:01:25 > 0:01:28So in the rainforest, many of the plants derive their nutrients
0:01:28 > 0:01:31and are fertilised from dust.
0:01:31 > 0:01:33In Kuwait, they are pioneering new ways
0:01:33 > 0:01:36of tackling the problem of dust storms...
0:01:36 > 0:01:40This plant can reduce the negative effect of dust.
0:01:41 > 0:01:43..while technology brings the prospect
0:01:43 > 0:01:45of daily dust-storm forecasts.
0:01:46 > 0:01:49So this is the sand dust storm warning and assessment system
0:01:49 > 0:01:51for Northern Africa, Middle East and Europe.
0:01:51 > 0:01:54As the world's climate becomes more extreme,
0:01:54 > 0:01:56scientists are urging action.
0:01:57 > 0:02:00It is the number-one killer,
0:02:00 > 0:02:02the number-one non-communicable disease
0:02:02 > 0:02:04that we are trying to tackle today.
0:02:05 > 0:02:09If it's coming your way, it's a case of, are you going to be suffocated?
0:02:21 > 0:02:23Oh, my God, this is crazy!
0:02:24 > 0:02:25Wow.
0:02:25 > 0:02:28Dust storms are frightening and dangerous.
0:02:28 > 0:02:30They can occur without warning,
0:02:30 > 0:02:34bringing transport to a standstill and disrupting daily life.
0:02:34 > 0:02:36Uh-oh. About to be engulfed!
0:02:36 > 0:02:39Dust can make people sick and it can kill.
0:02:43 > 0:02:47Sand and dust are generated in dry regions across the world
0:02:47 > 0:02:49but the greatest source is the Sahara Desert.
0:02:51 > 0:02:54The Sahara probably produces round about a half,
0:02:54 > 0:02:57something of that order, of the Earth's dust.
0:02:57 > 0:03:01And the reason it's there is because there's an old lake,
0:03:01 > 0:03:05that was there when conditions were wetter, that's dried up.
0:03:05 > 0:03:09And it's the material from the floor of that old lake,
0:03:09 > 0:03:14silt and little silica organisms called diatoms,
0:03:14 > 0:03:18that get blown away, high up into the air,
0:03:18 > 0:03:20and can travel huge distances.
0:03:24 > 0:03:27There's a range of countries, primarily neighbouring the Sahara,
0:03:27 > 0:03:30because this is the major source of sand and dust storms,
0:03:30 > 0:03:33both to the north and south, but equally to the east,
0:03:33 > 0:03:37where we're talking of Iraq, Iran, Syria, Kuwait, the Emirates,
0:03:37 > 0:03:40the Gulf states, Saudi Arabia.
0:03:40 > 0:03:43But increasingly, moving to the east, we run into the Stans,
0:03:43 > 0:03:45as we call them, Afghanistan, Turkmenistan,
0:03:45 > 0:03:49and here the difficulty is that they're affected in both directions,
0:03:49 > 0:03:52sand and dust being driven to the south from the Gobi Desert,
0:03:52 > 0:03:54from the Tibetan Plateau and all through Asia.
0:03:54 > 0:03:58So there's a whole range of countries with a long plume,
0:03:58 > 0:04:01starting from the western edge of the Sahara,
0:04:01 > 0:04:03all the way through and up to China.
0:04:06 > 0:04:10Dust has been blowing around the world for millennia.
0:04:10 > 0:04:12Dust storms are a natural phenomenon,
0:04:12 > 0:04:16but the world is getting hotter and, in many places, drier.
0:04:17 > 0:04:20Scientists see clear evidence that human activity
0:04:20 > 0:04:22is making dust storms worse.
0:04:22 > 0:04:25The science behind dust storms is fascinating.
0:04:25 > 0:04:31We think that 20% to 25% could be attributed to human activity.
0:04:31 > 0:04:33So, something called the Dust Bowl Syndrome,
0:04:33 > 0:04:37which is associated with poor land management, where the topsoil
0:04:37 > 0:04:40becomes aerosolised, like tiny, tiny, little aerosols,
0:04:40 > 0:04:43which means that the slightest amount of energy or wind
0:04:43 > 0:04:46can lift up the soil and effectively take those topsoils
0:04:46 > 0:04:48many thousands of kilometres.
0:04:49 > 0:04:54- ARCHIVE:- 'Clouds, rolling seas of anger move across vast territories
0:04:54 > 0:04:58'and drop their tragic burden of burning dust.'
0:05:08 > 0:05:11We had a big phenomenon, or tragedy,
0:05:11 > 0:05:14called The Dust Bowl of the United States in the 1930s.
0:05:19 > 0:05:22The American Dust Bowl is famous as a human-induced
0:05:22 > 0:05:24environmental disaster.
0:05:26 > 0:05:29In the 1920s and '30s,
0:05:29 > 0:05:33crops were planted on newly created farms on former grasslands
0:05:33 > 0:05:36but drought and over-farming on poor soils
0:05:36 > 0:05:38meant the crops failed year after year.
0:05:40 > 0:05:44With no vegetation, thousands of tonnes of soil blew away,
0:05:44 > 0:05:48creating choking storms of dust for days on end.
0:05:50 > 0:05:52How did it happen?
0:05:52 > 0:05:57Some unusually wet period made people think that water is available
0:05:57 > 0:06:00and you can plough anywhere you like and water would follow,
0:06:00 > 0:06:02and this was the dominant thinking.
0:06:04 > 0:06:09The Dust Bowl, primarily, was due to a drop in rainfall in the area.
0:06:09 > 0:06:12At the same time, the human population was migrating
0:06:12 > 0:06:15and using that area for agricultural purposes.
0:06:17 > 0:06:20And they were doing strip farming of the topsoils
0:06:20 > 0:06:22and then leaving them exposed.
0:06:23 > 0:06:24Farms were abandoned
0:06:24 > 0:06:27and people were forced to leave their homes for good.
0:06:31 > 0:06:34And the dust storms got so bad because of that,
0:06:34 > 0:06:38it drove legislation in 1935 to pass the Soil Conservation Act
0:06:38 > 0:06:39that Congress passed.
0:06:39 > 0:06:42And that prohibited that type of farming.
0:06:46 > 0:06:51A big driver of why the severity of the dust storms dropped over time
0:06:51 > 0:06:53was because it started raining again.
0:06:56 > 0:06:58The Americans instituted various things
0:06:58 > 0:07:01like shelter belts and windbreaks,
0:07:01 > 0:07:06which really dampened down the dust-storm activity
0:07:06 > 0:07:08in the 1940s and onwards
0:07:08 > 0:07:14and that does show that we can do something about it if we wish,
0:07:14 > 0:07:17in the right circumstances.
0:07:22 > 0:07:27Today, the Middle East is one of the areas worst affected by dust storms.
0:07:27 > 0:07:31It's in the path of sand and dust blowing from the Sahara,
0:07:31 > 0:07:32but the region itself
0:07:32 > 0:07:35is increasingly becoming a source of dust.
0:07:35 > 0:07:39Decreasing rainfall combined with the overuse of water for agriculture
0:07:39 > 0:07:42are making the soil dangerously dry.
0:07:43 > 0:07:47Why don't we get dust storms any time we have wind?
0:07:47 > 0:07:50Because we have a higher soil moisture.
0:07:53 > 0:07:58So soil moisture acts like a glue, it keeps these soil particles
0:07:58 > 0:08:02connected to each other, so the wind cannot lift them.
0:08:02 > 0:08:07As soon as you lose the moisture, you disconnect these particles
0:08:07 > 0:08:12and these particles are blown away easily whenever you have wind,
0:08:12 > 0:08:15so when you have a drought, when you have stronger winds
0:08:15 > 0:08:19and when you lose your soil moisture, you have a dust storm.
0:08:20 > 0:08:22PANICKED VOICES
0:08:27 > 0:08:31We have seen, in the Middle East and North Africa,
0:08:31 > 0:08:35more and more frequent dust storms and one of the reasons
0:08:35 > 0:08:40is that water resources in the region have become more scarce.
0:08:45 > 0:08:49Human intervention is one of the major reasons for this scarcity.
0:08:49 > 0:08:53Until 30 years ago, the marshlands of southern Iraq look like this.
0:08:54 > 0:08:57The marshes occupied 15,000 square kilometres
0:08:57 > 0:09:00between the Tigris and Euphrates rivers.
0:09:01 > 0:09:03The wetlands were deliberately drained
0:09:03 > 0:09:06by former Iraqi leader Saddam Hussein.
0:09:07 > 0:09:10They were partly restored but are now again threatened
0:09:10 > 0:09:14by the diversion of water for agriculture and the oil industry.
0:09:15 > 0:09:20Satellite maps show a gradual drying of the land over the past 15 years.
0:09:32 > 0:09:34Nations the world over see the control of water
0:09:34 > 0:09:37as key to growth and prosperity.
0:09:38 > 0:09:41Middle Eastern countries have ambitious programmes
0:09:41 > 0:09:44to build dams and water pipelines for drinking water,
0:09:44 > 0:09:47crop irrigation and hydroelectric power.
0:09:52 > 0:09:54Turkey has had a massive long-term project
0:09:54 > 0:09:58to harness the Tigris and Euphrates rivers, which start in Turkey
0:09:58 > 0:10:01and flow through neighbouring Syria and Iraq.
0:10:05 > 0:10:11The Ataturk Dam, completed in 1992, and a source of huge national pride,
0:10:11 > 0:10:13is one of the largest in the world.
0:10:16 > 0:10:20One-third of the Euphrates' former flow is now diverted for irrigation.
0:10:24 > 0:10:28Turkey's latest project is the Ilisu Dam on the River Tigris.
0:10:29 > 0:10:34When completed, it will submerge the ancient city of Hasankeyf,
0:10:34 > 0:10:37whose history goes back 12,000 years.
0:10:38 > 0:10:40Once, people travelled on the Tigris
0:10:40 > 0:10:44from here to Nineveh, Mosul and Babylon.
0:10:45 > 0:10:48There are international agreements promising Syria and Iraq
0:10:48 > 0:10:50a minimum amount of water,
0:10:50 > 0:10:54but, inevitably, the volume of water flowing downstream
0:10:54 > 0:10:56will be decreased.
0:10:57 > 0:11:00Most of this water goes into agriculture,
0:11:00 > 0:11:05so we want to irrigate and produce food in a dry area.
0:11:05 > 0:11:08So the amount of water we have in the Middle East
0:11:08 > 0:11:13is enough for satisfying our drinking and sanitation needs.
0:11:13 > 0:11:16It's not enough to produce food with it
0:11:16 > 0:11:19or make the region self-sufficient in food production,
0:11:19 > 0:11:22but this is something that the region has not understood well.
0:11:23 > 0:11:26Now, if you dry your soil,
0:11:26 > 0:11:29if you use a lot of water and waste a lot of water,
0:11:29 > 0:11:34then you should expect a punishment, which is called a dust storm,
0:11:34 > 0:11:39and that's something we have been punished for in the Middle East
0:11:39 > 0:11:42because of not using our water properly,
0:11:42 > 0:11:44because of losing soil moisture.
0:11:49 > 0:11:53One example of the consequences of poor water management
0:11:53 > 0:11:55is Lake Urmia in Iran.
0:11:56 > 0:11:59The lake, the largest in the Middle East,
0:11:59 > 0:12:02once supported wildlife and a tourist industry.
0:12:03 > 0:12:07With no outflow, its water became many times saltier than the oceans.
0:12:07 > 0:12:11Since the completion of dams restricting the inflow of water,
0:12:11 > 0:12:14Lake Urmia has shrunk dramatically.
0:12:18 > 0:12:24Lake Urmia is a good example of a modern environmental tragedy
0:12:24 > 0:12:27that was created by humans.
0:12:27 > 0:12:32We had a salt lake, which was one of the largest in the world.
0:12:32 > 0:12:36The dominant thinking was that rivers are flowing into the lake,
0:12:36 > 0:12:39this terminal lake, which has no effect, the water gets salty,
0:12:39 > 0:12:42let's use the water for a good purpose.
0:12:42 > 0:12:45Let's use it for farming, let's use it for the urban areas.
0:12:45 > 0:12:48What happened was that the lake got smaller
0:12:48 > 0:12:52and it becomes a big disaster that the whole region
0:12:52 > 0:12:56has been affected by and now a lot of investment should be made
0:12:56 > 0:13:01in order to restore the lake, if that is not only a dream.
0:13:03 > 0:13:07Sediments are very fine soils and once they dry out,
0:13:07 > 0:13:09they're easily mobilised into the atmosphere
0:13:09 > 0:13:13and some of the dustiest regions on the planet
0:13:13 > 0:13:17are usually due to dry lake beds. A good example, the United States.
0:13:17 > 0:13:18In the early 20th century,
0:13:18 > 0:13:23the city of Los Angeles tapped Lake Owens as a source for drinking water
0:13:23 > 0:13:26and a short time later that lake was dry, or almost totally dry,
0:13:26 > 0:13:29and to this day that is the number-one source of dust
0:13:29 > 0:13:32in the atmosphere in North America.
0:13:34 > 0:13:36Kuwait.
0:13:36 > 0:13:40This city lives under the shadow of dust storms, with around 21 a year.
0:13:42 > 0:13:47In summer, almost every day, people are breathing in dusty air.
0:13:49 > 0:13:53Kuwait is in the main pathway of winds bringing dust.
0:13:53 > 0:13:55It blows in from the Sahara in the west
0:13:55 > 0:13:58and, in summer, the shamal winds from the north-west
0:13:58 > 0:14:00bring dust from Syria and Iraq.
0:14:03 > 0:14:05It is one of the worst, in fact, in the region.
0:14:05 > 0:14:11Most of the trajectories of dust storms are passing through Kuwait.
0:14:11 > 0:14:15Dr Ali al-Dousari's research team know all about dust
0:14:15 > 0:14:17from first-hand experience.
0:14:17 > 0:14:21Dust builds up on cars and windows and on other surfaces
0:14:21 > 0:14:23such as solar panels.
0:14:23 > 0:14:25And it's getting worse.
0:14:26 > 0:14:30Inhaling all this dust has serious consequences.
0:14:30 > 0:14:33They have a great impact on human health.
0:14:34 > 0:14:39It's very bad for you to breathe in fine silica dust.
0:14:39 > 0:14:44It carries allergens which can, you know, be fungal spores or bacteria,
0:14:44 > 0:14:47which can affect you
0:14:47 > 0:14:51and cause hospital admissions or even death.
0:14:54 > 0:14:57Dr Ahmed al-Khabaz is an allergy specialist
0:14:57 > 0:15:00and consultant at the Kuwait Child and Allergy Clinic.
0:15:01 > 0:15:05Most of his patients suffer from the effects of dust and air pollution.
0:15:06 > 0:15:11Dust affects all people, irregard of their genetic predisposition.
0:15:11 > 0:15:13When you think about the air in Kuwait,
0:15:13 > 0:15:17the air in Kuwait is full of dust
0:15:17 > 0:15:22as well as chemicals that come from the oil industry,
0:15:22 > 0:15:25as well as pollution from cars.
0:15:25 > 0:15:30At the same time, you have a lot of pollen in that air,
0:15:30 > 0:15:33so, if you like, you can say you have a cocktail of chemicals
0:15:33 > 0:15:35into that air.
0:15:36 > 0:15:40Almost one in five of Kuwait's residents suffer from asthma.
0:15:42 > 0:15:45People live with the condition year round,
0:15:45 > 0:15:48but doctors see a spike in admissions
0:15:48 > 0:15:50when the dust storms arrive.
0:15:51 > 0:15:53During the dust-storm season,
0:15:53 > 0:15:57the number of patients visiting our clinic
0:15:57 > 0:16:00increases to double the usual day.
0:16:00 > 0:16:03And some of them, they get severe attacks
0:16:03 > 0:16:07that requires hospital admission and intensive care.
0:16:09 > 0:16:12Kuwait resident Mokhtar al-Hijrah,
0:16:12 > 0:16:16has suffered from dust-related asthma for 15 years.
0:16:17 > 0:16:21TRANSLATION:
0:17:02 > 0:17:05But it's hard to escape the dust, even inside.
0:17:05 > 0:17:07Resident Khalid Al Ameri
0:17:07 > 0:17:10shows some of the measures Kuwaitis use
0:17:10 > 0:17:13to try to prevent dust particles getting into their homes.
0:18:20 > 0:18:24Countries across the world see an increase in hospital admissions
0:18:24 > 0:18:26because of respiratory problems.
0:18:26 > 0:18:30The very young and the very old are particularly vulnerable.
0:18:31 > 0:18:35For them, poor air quality can be life-threatening.
0:18:36 > 0:18:39With nearly seven million people dying prematurely
0:18:39 > 0:18:43because of air quality, much of which is a complex mixture
0:18:43 > 0:18:47of dust that has got pollutants carried with it,
0:18:47 > 0:18:49means that it is the number-one killer,
0:18:49 > 0:18:52the number-one non-communicable disease
0:18:52 > 0:18:54that we are trying to tackle today.
0:19:04 > 0:19:08Back in Kuwait, Dr al-Dousari's team collect dust for analysis
0:19:08 > 0:19:12from nearly 50 sites across the country.
0:19:12 > 0:19:14Dust is complex material.
0:19:14 > 0:19:17Its chemical and mineral composition varies
0:19:17 > 0:19:19depending on where it comes from.
0:19:19 > 0:19:22These variations have a bearing on its health impact.
0:19:24 > 0:19:28The size of dust particles is key in assessing their impact on health.
0:19:28 > 0:19:30The Kuwaiti scientists measure the size range
0:19:30 > 0:19:32by looking at the light scattered
0:19:32 > 0:19:35when a laser beam is shone through the sample.
0:19:35 > 0:19:38The size of the particle is very important
0:19:38 > 0:19:41in causing respiratory problems.
0:19:42 > 0:19:4785% of dust size in Kuwait is ten micrometres
0:19:47 > 0:19:51and that's the size that usually cause respiratory complaints
0:19:51 > 0:19:53and exacerbation of asthma.
0:19:55 > 0:19:59When we breathe in dust, particles smaller than ten micrometres,
0:19:59 > 0:20:03the PM 10 particles, become lodged in the lungs,
0:20:03 > 0:20:05causing breathing difficulties.
0:20:05 > 0:20:08Even smaller particles, PM 2.5,
0:20:08 > 0:20:11can actually cross directly into our bloodstream.
0:20:12 > 0:20:17The small particles, they interfere with the gas exchange of the lung
0:20:17 > 0:20:21and result into severe respiratory diseases.
0:20:22 > 0:20:25Scientists at institutions across the world
0:20:25 > 0:20:28are doing further tests that add to the analysis.
0:20:30 > 0:20:34Claire Corkhill is a mineralogist at the University of Sheffield
0:20:34 > 0:20:35in the UK.
0:20:35 > 0:20:39She leads a laboratory studying soil and dust particles.
0:20:39 > 0:20:41What we're looking at now is the dust
0:20:41 > 0:20:44under a scanning electron microscope
0:20:44 > 0:20:47and at the moment we're magnified by 300 times.
0:20:47 > 0:20:50So the scale bar on this image is 50 microns across
0:20:50 > 0:20:53and so these particles are really, really very small.
0:20:53 > 0:20:57We have some individual ones but they also agglomerate all together
0:20:57 > 0:20:58in big clumps.
0:20:58 > 0:21:02So you can see there's a whole different distribution of sizes,
0:21:02 > 0:21:05some of them very small and some of them a lot larger.
0:21:05 > 0:21:07With another technique, X-ray diffraction,
0:21:07 > 0:21:11Claire can tell what mineral types are present in the dust sample.
0:21:11 > 0:21:14Minerals are highly structured and different ones
0:21:14 > 0:21:16can have different effects when we breathe them in.
0:21:16 > 0:21:20So this is the diffraction pattern from the dust sample
0:21:20 > 0:21:23and what we've been able to identify are four different phases
0:21:23 > 0:21:25and these are gypsum, which is calcium sulphate,
0:21:25 > 0:21:28there's also calcite, which is calcium carbonate,
0:21:28 > 0:21:30there is quartz, which is probably
0:21:30 > 0:21:33the main phase that's present in this material,
0:21:33 > 0:21:36and also a very small amount of a type of mica called muscovite,
0:21:36 > 0:21:38which is a clay material.
0:21:39 > 0:21:43Quartz in dust can be in the form of tiny, sharp crystals,
0:21:43 > 0:21:45which can cause severe irritation.
0:21:45 > 0:21:49Quartz is responsible for upregulation
0:21:49 > 0:21:52of the inflammatory cells in the respiratory system.
0:21:52 > 0:21:56Aluminium and magnesium in the dust
0:21:56 > 0:21:59are responsible for causing mucus irritation
0:21:59 > 0:22:01in the upper and lower airways.
0:22:02 > 0:22:05The dust isn't purely mineral.
0:22:05 > 0:22:08Sticking to these dust particles there may be material
0:22:08 > 0:22:10such as pollen and bacteria.
0:22:11 > 0:22:16Studies show that these contaminants can make breathing problems worse.
0:22:16 > 0:22:19Well, you go out into the desert and you look at...
0:22:19 > 0:22:21you see a lot of dirt in topsoil
0:22:21 > 0:22:23and you don't see any growth.
0:22:24 > 0:22:28No trees, no brush, no anything, and you think it's sterile.
0:22:28 > 0:22:31Well, it's not, even in the most inhabitable regions,
0:22:31 > 0:22:34if you reach down and pick between your index finger and your thumb,
0:22:34 > 0:22:37that would be about a gram of topsoil,
0:22:37 > 0:22:41you would have anywhere from 10,000 to a billion bacterial cells.
0:22:44 > 0:22:47Dust is clearly a major hazard,
0:22:47 > 0:22:50so there's an urgent need to understand the behaviour
0:22:50 > 0:22:53of dust storms to help people cope with their impact.
0:22:58 > 0:23:01Three, two, one.
0:23:01 > 0:23:04Main engines start and liftoff.
0:23:12 > 0:23:15One of the best ways to study dust storms
0:23:15 > 0:23:17is by satellites orbiting the Earth.
0:23:18 > 0:23:21People didn't understand the intensity
0:23:21 > 0:23:24and how far these storms could move until we had satellite imagery.
0:23:28 > 0:23:31NASA has over 20 Earth-observing satellites
0:23:31 > 0:23:33that are monitoring constantly
0:23:33 > 0:23:37different components of the energy and water and carbon cycles.
0:23:37 > 0:23:40Using satellites, we're able to get a global picture of the land surface
0:23:40 > 0:23:43and different components of the land surface.
0:23:43 > 0:23:47For example, you can monitor the type and amount of vegetation.
0:23:47 > 0:23:53In addition, you can also tell how wet the soil is by using microwaves.
0:23:53 > 0:23:55So if you know how wet the surface is,
0:23:55 > 0:23:58then you have a better idea of the intensity and duration
0:23:58 > 0:24:01and locations of potential dust storms.
0:24:03 > 0:24:07NASA's Goddard Space Center is the largest organisation in the world
0:24:07 > 0:24:11monitoring the Earth, the solar system and the universe.
0:24:12 > 0:24:1410,000 people work here
0:24:14 > 0:24:18and several hundred scientists specialise in looking at the Earth.
0:24:20 > 0:24:23With the information satellites gather from land, sea and air,
0:24:23 > 0:24:25scientists build computer models
0:24:25 > 0:24:29that help them simulate past and future conditions.
0:24:30 > 0:24:32Dr Peter Colarco is one of the team
0:24:32 > 0:24:35studying particles in the atmosphere.
0:24:35 > 0:24:39So this is an animation from a global earth system model
0:24:39 > 0:24:41that we run here at NASA.
0:24:41 > 0:24:44What we're simulating in this are the distributions
0:24:44 > 0:24:47of what we call aerosols, or particles in the atmosphere.
0:24:47 > 0:24:51And the different colours represent different kinds of these particles
0:24:51 > 0:24:54and they come from all kinds of different sources.
0:24:54 > 0:24:56So the blue colours are from sea spray
0:24:56 > 0:24:59that's blown up by the winds at the surface of the sea.
0:24:59 > 0:25:01The greener colours come from smoke sources,
0:25:01 > 0:25:05so there we have individual fires that are going off in the model
0:25:05 > 0:25:07and emitting smoke into the atmosphere
0:25:07 > 0:25:09and it's transported over long distances.
0:25:09 > 0:25:12The whiter colours correspond to what we would call
0:25:12 > 0:25:14anthropogenic pollutants,
0:25:14 > 0:25:17so things that come from power plants or car emissions
0:25:17 > 0:25:19and so you can see places, especially in China
0:25:19 > 0:25:22or on the east coast of the United States
0:25:22 > 0:25:24or even in Europe, where a lot of these pollutants
0:25:24 > 0:25:26are emitted and transported.
0:25:26 > 0:25:30And finally, the redder colours that we have correspond to dust storms
0:25:30 > 0:25:32and so in that case, what we're looking at
0:25:32 > 0:25:36is the effect of the surface winds blowing across a region
0:25:36 > 0:25:39that has a lot of fine particles that can be blown up into the air
0:25:39 > 0:25:42and blown by the winds over very long distances.
0:25:43 > 0:25:46Using models like this helps scientists understand
0:25:46 > 0:25:49what's happening in the Earth's atmosphere.
0:25:49 > 0:25:52Other projects concentrate on collecting actual data
0:25:52 > 0:25:55about atmospheric particles.
0:25:55 > 0:26:00Dr Robert Levy has been working on a long-term global aerosol record.
0:26:02 > 0:26:06So this is a time series from the MODIS Terra satellite.
0:26:06 > 0:26:09We're trying to create global observations of aerosol.
0:26:09 > 0:26:13These are not models, these are based on camera-like images.
0:26:13 > 0:26:18How it works is satellites measure light reflected from the Earth
0:26:18 > 0:26:20and you can see that there are places on the globe
0:26:20 > 0:26:23where you see lots of aerosol, which is the bright orange colour.
0:26:23 > 0:26:26And you can see the hot spots around the globe,
0:26:26 > 0:26:29you see the dust in Africa, biomass burning in the Amazon.
0:26:29 > 0:26:32What we don't have from the satellite
0:26:32 > 0:26:34is exactly what it's made out of.
0:26:34 > 0:26:38You can get a sense of what kind it is, if it's dust, smoke, pollution.
0:26:38 > 0:26:42One place that you do see, at least in the 15-year record we have,
0:26:42 > 0:26:45is there seems to be an increase in the Middle East,
0:26:45 > 0:26:48along the Arabian Peninsula, in that region,
0:26:48 > 0:26:51and it seems to be a significant increase.
0:26:53 > 0:26:56NASA's studies back up what people on the ground
0:26:56 > 0:26:58can see for themselves.
0:26:58 > 0:27:00Oh, look at that! Look at that!
0:27:01 > 0:27:05These satellite studies are now being put to practical use.
0:27:05 > 0:27:07Look at that!
0:27:14 > 0:27:17NASA shares its data with other research groups
0:27:17 > 0:27:21who are developing a global sand and dust storm early warning system.
0:27:22 > 0:27:25This former church in the Spanish city of Barcelona
0:27:25 > 0:27:27is now a world centre for science.
0:27:30 > 0:27:35The interior is taken up by the massive MareNostrum 3 supercomputer,
0:27:35 > 0:27:38used by research scientists across the world.
0:27:41 > 0:27:43One project is to predict dust storms,
0:27:43 > 0:27:47in this case for Europe, the Middle East and North Africa.
0:27:50 > 0:27:54Other centres in China, Japan and Korea cover the Asia region
0:27:54 > 0:27:56and the aim, ultimately, is to alert people
0:27:56 > 0:27:59when a dust storm is expected.
0:28:01 > 0:28:03The role of the Barcelona supercomputer centre
0:28:03 > 0:28:07is to provide every day forecasts of sand and dust storms
0:28:07 > 0:28:09over North Africa, Middle East and Europe.
0:28:10 > 0:28:12The dust storm or the dust forecasting
0:28:12 > 0:28:15is very similar to a weather forecast.
0:28:15 > 0:28:20Precipitation, but also the wind regimes, right,
0:28:20 > 0:28:23you know, based on different meteorological scenarios.
0:28:23 > 0:28:26If you have more wind or less wind,
0:28:26 > 0:28:29you're going to have more or less dust depending on these anomalies.
0:28:29 > 0:28:33Basically, what we're producing now are three-day forecasts.
0:28:36 > 0:28:39This is a forecast from the Barcelona group
0:28:39 > 0:28:41for three days in June 2016.
0:28:42 > 0:28:46The high concentrations are yellow and brown
0:28:46 > 0:28:49but the resolution and accuracy aren't yet up to the standard
0:28:49 > 0:28:52or detail of weather forecasts.
0:28:53 > 0:28:57Probably, and this is what's going to probably happen in the future,
0:28:57 > 0:28:59we're going to have probabilistic forecasting,
0:28:59 > 0:29:02so we're going to have an ensemble of forecasts
0:29:02 > 0:29:05with different regional conditions at very high resolution
0:29:05 > 0:29:08and we will be able to provide a probabilistic forecast
0:29:08 > 0:29:12as this is happening now for weather forecasting for precipitation.
0:29:12 > 0:29:16For example, you have seen that we have a 30% chance
0:29:16 > 0:29:19of precipitation in this area, or a 70% chance,
0:29:19 > 0:29:22so that's the idea also with dust storms in the future,
0:29:22 > 0:29:27particularly the storms that are really very difficult to capture,
0:29:27 > 0:29:31which are the finer scale, but that can be particularly intense.
0:29:31 > 0:29:36In fact, our dust forecast requires even more computing time
0:29:36 > 0:29:39than a weather forecast would require.
0:29:39 > 0:29:43It's only by having a machine like the one we have behind us
0:29:43 > 0:29:47that we can afford to perform the best dust forecasts
0:29:47 > 0:29:51and not only the dust forecasts themselves, but the archiving
0:29:51 > 0:29:54and the management of the data that's being produced,
0:29:54 > 0:29:59which is in the order of gigabytes of data every single day.
0:30:00 > 0:30:03The Barcelona and NASA scientists know their forecasts
0:30:03 > 0:30:05would be helped if they had better local data
0:30:05 > 0:30:07from the countries concerned.
0:30:07 > 0:30:10Of course, the other thing that we need to bring in
0:30:10 > 0:30:12is more data that comes from the ground
0:30:12 > 0:30:15that will help us refine things like the maps that we use
0:30:15 > 0:30:18for our dust sources and even have them evolving over time
0:30:18 > 0:30:22by including some information about vegetation and economics
0:30:22 > 0:30:25and how that will influence things like dust sources.
0:30:32 > 0:30:34War makes data collection impossible.
0:30:35 > 0:30:38Conflicts in Iraq and, more recently, Syria,
0:30:38 > 0:30:41have actually worsened the problem of dust storms.
0:30:42 > 0:30:46And the energies of the people are consumed by conflict and survival.
0:30:53 > 0:30:57The problem that we have in our region is the conflicts,
0:30:57 > 0:31:03the instability and the ongoing violence and terrorism.
0:31:06 > 0:31:08And that is aggravating the situation.
0:31:11 > 0:31:13Unfortunately, a lot of the tracked vehicles
0:31:13 > 0:31:17and the driving over the desert surface by the combatants
0:31:17 > 0:31:21has disturbed the desert surface and made it worse.
0:31:24 > 0:31:29The effect of war activities, especially in Iraq and Syria,
0:31:29 > 0:31:33caused a huge amount of vegetation to have been destroyed.
0:31:33 > 0:31:35I'm talking about native vegetation,
0:31:35 > 0:31:40which make new sources of dust, never there in the past.
0:31:45 > 0:31:51If we have a dust storm generated in a place like Syria and Iraq,
0:31:51 > 0:31:56it is very different from a dust storm which is generated
0:31:56 > 0:31:59from a place like Oman or UAE
0:31:59 > 0:32:02because in places like Iraq and Syria,
0:32:02 > 0:32:04we have had conflicts for years,
0:32:04 > 0:32:09so we have toxic elements which could be attached to the surface.
0:32:09 > 0:32:13Dust moves many thousands of kilometres and, in moving,
0:32:13 > 0:32:17picks up all kinds of what we would call legacy chemicals.
0:32:17 > 0:32:20It could be depleted uranium, it could be pesticides,
0:32:20 > 0:32:23it could be hazardous chemicals, heavy metals, contaminants.
0:32:23 > 0:32:26And the dust itself becomes like a small nucleus.
0:32:26 > 0:32:31It attracts and sticks together and brings pollutants together.
0:32:31 > 0:32:35So as those big areas of dust get lifted and moved,
0:32:35 > 0:32:39they become part of the ambient air quality problems
0:32:39 > 0:32:40that many cities have.
0:32:41 > 0:32:44Scientists have also observed an increase in temperature
0:32:44 > 0:32:47in the Middle East over the past 80 years.
0:32:48 > 0:32:52And over the same period, a decrease in rainfall.
0:32:52 > 0:32:55Even before the wars, these conditions were damaging,
0:32:55 > 0:32:58particularly for agriculture.
0:32:58 > 0:33:01Many farmers abandoned lands, particularly in Syria,
0:33:01 > 0:33:05and, erm...those farmers went to the cities,
0:33:05 > 0:33:09so there's a lot of land abandoned there as well.
0:33:09 > 0:33:11This creates wind erosion.
0:33:11 > 0:33:14What we had before is agricultural fields.
0:33:14 > 0:33:16These are now exposed to wind erosion.
0:33:17 > 0:33:20Syria wasn't before a source area.
0:33:20 > 0:33:22Now it's a huge area of dust.
0:33:22 > 0:33:26Also, the area between Zagros Mountains and Tigris River,
0:33:26 > 0:33:30we found a huge amount because this was affected by war activities,
0:33:30 > 0:33:32multiple war activities.
0:33:32 > 0:33:35So drained farms and abandoned farms
0:33:35 > 0:33:39became a huge source of dust, in fact, from this region.
0:33:39 > 0:33:43Once the land is dried up, any sort of wind,
0:33:43 > 0:33:45any strong wind in dry times
0:33:45 > 0:33:48can blow the dust particles,
0:33:48 > 0:33:54so people in Khuzestan now have one-third of their days a year dusty
0:33:54 > 0:33:58and, you know, living in those areas is not pleasant any more.
0:33:59 > 0:34:03The city of Ahvaz in Khuzestan, southwestern Iran,
0:34:03 > 0:34:06is now one of the most polluted cities on the planet,
0:34:06 > 0:34:09partly because of dust blowing in from Iraq.
0:34:11 > 0:34:15We've been witnessing a steady increase
0:34:15 > 0:34:18in the number of incidences
0:34:18 > 0:34:21but also in the intensity of dust storms,
0:34:21 > 0:34:23maybe in the past two decades.
0:34:23 > 0:34:29And so it's not only affecting our border cities but now, sometimes,
0:34:29 > 0:34:33the dust storms are moving ahead into the capital, Tehran.
0:34:38 > 0:34:41On June 2nd, 2014,
0:34:41 > 0:34:44Tehran was hit by a spectacular dust storm.
0:34:44 > 0:34:46CAR ALARMS
0:34:47 > 0:34:50Five people were killed and 30 injured.
0:34:50 > 0:34:53Flights were cancelled, there were numerous car accidents
0:34:53 > 0:34:55and the city was plunged into darkness.
0:34:58 > 0:35:02When this happens in a nation's capital, people take notice.
0:35:03 > 0:35:05As well as the social impact,
0:35:05 > 0:35:09the economic cost of events like this is devastating.
0:35:18 > 0:35:22Economists calculate that dust storms cost the Middle East
0:35:22 > 0:35:26and North Africa around 12 billion US dollars every year.
0:35:28 > 0:35:31So there's a pressing need for practical remedies.
0:35:33 > 0:35:36One of the first priorities is to tackle desertification.
0:35:42 > 0:35:45In Kuwait, Ali al-Dousari's team are experimenting
0:35:45 > 0:35:49with native desert plants to try to stabilise the soil.
0:35:50 > 0:35:53These drought-tolerant plants have extensive root systems,
0:35:53 > 0:35:56which help prevent soil from blowing away.
0:35:56 > 0:35:58This is Al-Liah area.
0:35:58 > 0:36:01It was a quarry area in the past in Kuwait.
0:36:02 > 0:36:05Quarrying was prohibited in Kuwait in 2003.
0:36:05 > 0:36:07So all the quarries was dumped
0:36:07 > 0:36:10and zero vegetation was in this area before.
0:36:10 > 0:36:15Now the area is rehabilitated again by using native plants
0:36:15 > 0:36:19in order to form a very good native life in the region.
0:36:20 > 0:36:24We planted about 110,000 native plants in the area.
0:36:24 > 0:36:29These native plants capture a huge amount of dust and sand
0:36:29 > 0:36:31around the plant.
0:36:31 > 0:36:35It wasn't there before so this kind of sediment
0:36:35 > 0:36:39is formed by the dust and sand transported by wind.
0:36:39 > 0:36:41It contains a lot of nutrients.
0:36:41 > 0:36:45It reaches up to 9% of organic matter inside it.
0:36:46 > 0:36:49Native plants is a major solution, in fact.
0:36:49 > 0:36:53Let's give an example, Haloxylon salicornicum as a plant.
0:36:53 > 0:36:57It can control up to 10 cubic metres of sand and dust.
0:36:57 > 0:37:01This is a single plant. What if it's thousands of plants?
0:37:06 > 0:37:08Satellite data can also play a role
0:37:08 > 0:37:11in improving land and water management.
0:37:12 > 0:37:16In 2015, NASA launched a new satellite.
0:37:17 > 0:37:20The satellite makes direct measurements of the soil moisture
0:37:20 > 0:37:22every few days.
0:37:23 > 0:37:26If you understand how much water's in the land surface,
0:37:26 > 0:37:30that can really help you forecasting and monitoring droughts and floods.
0:37:30 > 0:37:33What we're seeing here, the red and yellow colours
0:37:33 > 0:37:37represent precipitation and the orange and blue colours
0:37:37 > 0:37:40are the changes in soil moisture from the average.
0:37:40 > 0:37:42Blue colours represent wetter areas
0:37:42 > 0:37:45and red colours represent drier areas.
0:37:45 > 0:37:49So if you have a direct observation of the amount of moisture
0:37:49 > 0:37:52in the land surface and you can improve your understanding
0:37:52 > 0:37:54of the amount of moisture in the root zone,
0:37:54 > 0:37:56that's a very, very important variable
0:37:56 > 0:37:59for improving your understanding of crops.
0:38:01 > 0:38:04NASA hopes that when this information
0:38:04 > 0:38:05is made available to farmers,
0:38:05 > 0:38:09it will improve land management, reducing the need for irrigation.
0:38:13 > 0:38:17For people living in dust-storm areas, new technology could help.
0:38:17 > 0:38:21Nowadays it's possible to check the dust forecasts online.
0:38:22 > 0:38:24These forecasts from the Barcelona website
0:38:24 > 0:38:27are part of the global early warning system.
0:38:27 > 0:38:29They're updated daily.
0:38:29 > 0:38:34It provides a map with details of dust concentration
0:38:34 > 0:38:36in the Middle East and North Africa.
0:38:36 > 0:38:40If we zoom in around Syria and southern part of Iran,
0:38:40 > 0:38:42we see a high concentration of dust.
0:38:42 > 0:38:45The yellow colour shows higher concentration,
0:38:45 > 0:38:48the dark brown is very high concentration of dust,
0:38:48 > 0:38:52which is beyond, well beyond WHO limits,
0:38:52 > 0:38:56so you would see what happens every hour in the next 72 hours.
0:38:57 > 0:39:00The forecasts are becoming ever more accurate.
0:39:02 > 0:39:05In future, they could help airports,
0:39:05 > 0:39:08schools and emergency services to plan ahead.
0:39:15 > 0:39:19Atmospheric dust has always been with us and there are some benefits.
0:39:20 > 0:39:23There's some very positive impacts from dust storms
0:39:23 > 0:39:25blowing around the planet.
0:39:25 > 0:39:28Many of the soils in the Caribbean islands,
0:39:28 > 0:39:30the clays came from North Africa
0:39:30 > 0:39:34and enabled the pre-Columbian Indians to build clay pottery.
0:39:34 > 0:39:37And without that dust blowing across and building up in the soils,
0:39:37 > 0:39:40the clay wouldn't be in the Caribbean. You wouldn't find it.
0:39:42 > 0:39:45Dust also contains valuable nutrients for plants.
0:39:47 > 0:39:50So in the rainforest, from North Africa, the dust blows over,
0:39:50 > 0:39:54it goes into South America during the northern hemisphere's winter
0:39:54 > 0:39:58and moves down in there and many of the plants derive their nutrients
0:39:58 > 0:40:00and are fertilised from dust.
0:40:00 > 0:40:02And the same with Asian dust blowing across,
0:40:02 > 0:40:06fertilises some of northern Hawaiian islands' rainforests
0:40:06 > 0:40:09and sustains them, so there is some very positive things.
0:40:10 > 0:40:13Scientists in America are investigating the effect
0:40:13 > 0:40:17of Saharan dust, which blows across the Atlantic every summer.
0:40:21 > 0:40:25Dr Erin Lipp's team are looking at whether this dust has an impact,
0:40:25 > 0:40:28good or bad, on the coral reefs off the coast of Florida.
0:40:32 > 0:40:36The dust that we see in south Florida is from the Saharan region
0:40:36 > 0:40:39and, really, July and August is the peak time
0:40:39 > 0:40:41when we tend to see dust events.
0:40:41 > 0:40:43Typically it will look like a hazy day
0:40:43 > 0:40:46and to somebody who doesn't know that there's dust in the air
0:40:46 > 0:40:50or isn't thinking about it, they'll just say, "It's a hazy day."
0:40:50 > 0:40:51But you can tell
0:40:51 > 0:40:54and if you're collecting aerosol samples on filters,
0:40:54 > 0:40:57you can actually see that your filters start turning orange
0:40:57 > 0:40:58during dust events.
0:40:59 > 0:41:03Each summer, the scientists return to the same coral reefs
0:41:03 > 0:41:05to study the health of the coral.
0:41:09 > 0:41:11They've seen worrying changes.
0:41:11 > 0:41:13The economy of the Florida Keys
0:41:13 > 0:41:16is almost entirely based on having a healthy coral reef.
0:41:16 > 0:41:19Whether it's because commercial or recreational fishers
0:41:19 > 0:41:22are going out to the reef and that's where the fish stocks are
0:41:22 > 0:41:23or because of diving
0:41:23 > 0:41:26and having a picturesque place to be in the water,
0:41:26 > 0:41:30we've seen a very large decline in the corals over the last 20 years.
0:41:30 > 0:41:33They're not in a particularly good state right now.
0:41:33 > 0:41:36The dust might be involved in the deterioration.
0:41:36 > 0:41:37It's a hypothesis that we have.
0:41:38 > 0:41:41So we're looking at changes in water chemistry.
0:41:41 > 0:41:43As the dust is deposited, we're looking at changes
0:41:43 > 0:41:47in the amount of trace metals that are there, especially iron,
0:41:47 > 0:41:49which is very limiting in marine waters
0:41:49 > 0:41:52and there's a lot of organisms that require iron to grow.
0:41:52 > 0:41:54The Saharan dust contains iron
0:41:54 > 0:41:59and this iron stimulates an explosion in bacterial populations.
0:42:00 > 0:42:01The team wants to know
0:42:01 > 0:42:05if this contributes to the damage to the coral.
0:42:05 > 0:42:08It's a complex picture and it's not yet clear.
0:42:08 > 0:42:11I grew up in South Florida and it was quite common in news reports
0:42:11 > 0:42:13for the weather forecast to say,
0:42:13 > 0:42:17"There's Saharan dust and there's going to be beautiful sunsets."
0:42:17 > 0:42:19That was my image of Saharan dust.
0:42:19 > 0:42:22So I think there may be a particular draw.
0:42:22 > 0:42:25It's a unique aspect that people don't necessarily think of here
0:42:25 > 0:42:29and it makes for very picturesque views when you're on the water.
0:42:38 > 0:42:41Science can play a part in understanding,
0:42:41 > 0:42:44predicting and preventing dust storms.
0:42:44 > 0:42:48This knowledge then needs to be used by policymakers.
0:42:49 > 0:42:52We are very good in developing technologies,
0:42:52 > 0:42:56launching satellites and doing things, but when it comes to policy,
0:42:56 > 0:43:00many times we act stupidly, we become stupid,
0:43:00 > 0:43:02we don't understand the realities on the ground
0:43:02 > 0:43:06or we don't care about the long-term consequences of our policy.
0:43:07 > 0:43:11Very, very clearly, desertification is something we need to tackle
0:43:11 > 0:43:15at a very local level and it's mundane things - planting trees,
0:43:15 > 0:43:19using proper irrigation, making sure that we have a vegetative cover -
0:43:19 > 0:43:22that avoids the aerosolisation of the topsoil.
0:43:25 > 0:43:27Of course, dust is a natural phenomenon,
0:43:27 > 0:43:29it's always going to be there.
0:43:29 > 0:43:32You're going to have natural desert, it's going to blow up dust,
0:43:32 > 0:43:35it's going to transport this dust toward different regions,
0:43:35 > 0:43:39but we can do a lot with land-conservation practices.
0:43:39 > 0:43:43They still have some dust storms in the US, but not of that size
0:43:43 > 0:43:45because they have better land-management practices.
0:43:45 > 0:43:48The same has to happen in the Middle East.
0:43:48 > 0:43:50PEOPLE SHOUT
0:43:51 > 0:43:55This is a multinational problem and needs a multinational solution,
0:43:55 > 0:43:59so the countries in the region have to come together
0:43:59 > 0:44:00and solve this problem.
0:44:03 > 0:44:07Dust storms are part of a wider environmental problem.
0:44:07 > 0:44:11The wars and conflicts of the region will eventually be over.
0:44:11 > 0:44:16When they are, the environmental problems won't have gone away.