Nature always bats last
By: Thuận Sarzynski
Tags: Society, Nature, Cities, Climate Change, Environment

Nature is a beautiful thing. We can hike in its landscapes, take photos of its flowers and pet its animals. Nature is also generous, we harvest its fishes and fruits, we excavate its minerals and we cut its trees. We often assume that Nature is a docile being, always keen to satisfy our wants.

Still, Nature can become angry and very scary. Nature can kill and disturb human societies. Nature will always set the rules and enforce them. As my good North American friend told me:

“Nature always bats last”

Volcanoes can put the world on fire

The large amount of material that a volcano can throw up from the Earth mantle is really impressive. It’s enough to create islands or disturb the climate for few years.

During an eruption, volcanoes make the ground tremble and create fractures around their vent. These first signs of an eruption can already cause harms to people living in the direct neighborhood of a volcano. Imagine a yawning fissure opening right through your house or on the road few step ahead from your car… Waking a volcano up is definitely not a good idea.

Once awake, a volcano can vomit large amount of lava which is more or less fast depending on its temperature, water and silica content. In a good channel, it can reach a speed of 40 miles an hour! Better run fast or climb onto your house’s roof! Lava is usually relatively slow and therefore not a direct threat to human beings but it can ravage properties and incurs high costs to insurances.

The deadliest kind of volcanoes are grey. Grey because they erupt large amount of fast running hot ashes (which are grey). First, they throw up hot ashes in the sky as a pyroclastic surge which then fall down on the volcano slopes and destroy surrounding towns. Everybody remembers how in 79 AD, Mount Vesuvius transformed the people of Pompeii and Herculaneum into human statues of dust. A scary story.

Closer to us, in 1991, the eruption of Mount Pinatubo in Philippines killed 847 people mainly because of roof collapsing under ashes weight. The dust of the volcano had a long term effect as well since it decreased the world temperature of 0.5°C in the following 2 years.

In April 2010, Eyjafjallajokull eruption completely disturbed European air transport with a loss of 4.7 billion dollars in one week because of the waste of perishable goods, the cancelled leisure and business travel, and the suspended work of industrial production plants.

Super volcanoes which are big volcanoes erupting large volumes of materials, can have an even greater impact on the world climate. Mount Tambora which erupted in 1815 caused a drop in the global temperature of 0.5–0.7°C for three years. This cold climate led to famines, epidemics and the creation of the Gothic literature. There was so much dust in the air that the year 1816 was called “the year without summer”.

It’s not easy to prevent a volcano to erupt, I would even say it’s impossible. The only thing we can do is monitor it, try to predict its next eruption and evacuate people on time so there won’t be any deaths. Property damages are unavoidable unless we advise people to not settle next to volcanoes. Monitoring volcanoes involves high technology, satellite imagery, sound shocks, tomography etc… Technology is pretty good to accurately predict future eruption. Still, we can’t do anything against a large-scale super volcano eruption which could wipe out humankind in a night.

Photo by Marc Szeglat on Unsplash

Earthquake takes place when two tectonic plates are moving in opposite direction creating friction and releasing of energy when they slip on each other. The elastic property of the tectonic plate causes ground shaking after the energy release. Ground shaking can make building fall down and kill people, that’s why earthquake never kills people but buildings do.

Earthquake also affects the ground by making it behave like quick sand, this is called liquefaction. Liquefaction is really impressive and the ground can literally completely swallow buildings.

Earthquake produces landslide by disrupting the organization and cohesion of the ground layers which can slip downward destroying everything on their way.

Liquefaction of the ground under a building © Wikimedia commons

Landslides are slippery layers of ground on the ground

Gravity can be an annoying thing. Gravity keeps our feet on the ground but it also pushes rocks and sediments downward. This movement downward can have various forms like a slow creep or a fast rock fall. The speed and strength of the movement depend on the mass of the material but also on the amount of water it contains. Water often plays the role of lubricant, pushing grains apart and reducing cohesion among layers of materials.

Landslides are deadly and costly, on average 7500 deaths are caused by landslides every year and the material loss is estimated around 20 billion dollars.

The way human being treat the ground often increases the risk of landslides. We move materials from one place to another, we mine and we built houses. We take out weight here, add some weight there, and sometimes water everything by diverting rivers or creating lakes. Like earthworms burrowing the soil, we are engineers of the ground. But contrary to earthworm whose action is beneficial for the ecosystems, ours is negatively affecting the environment.

Tsunami: the wave in the harbor

Tsunami are high waves coming on the continent from the sea. They mainly threaten coastal population. They are produced by disturbances such as undersea thrust faults, landslides, volcanic eruption or asteroid impacts. For example, when a large amount of land or magma go into the water it creates a wave that can travel through the sea and reach human population on the opposite continent or island. With global warming and the melting of the arctic, falling ice cube also creates tsunami which can threaten European coastal cities. The time between the original disturbance and shock caused by the large wave on the coast often takes few hours. This is an opportunity to evacuate people and mitigate the damages of the wave. Scientists can also predict the creation of new faults and landslides. The strength of a tsunami depends on the volume of water displaced during landslides or undersea thrust faults. The size of the fault and the water depth are important parameters as well.

Wet floods

Rivers are a key component of our lives. They bring water from the mountainous region to our fields and settlements so we can grow food and drink freshwater. Water can become threatening as well when it comes in places where it’s not expected. For example, in cities where the ground is sealed by a layer of concrete, water cannot infiltrate and thus may create great damages along its path. Urbanization has significantly changed the course of the water. It has increased the maximum retained water volume and the speed of discharge, it has also reduced the time lag between rainfalls and floods.

City planners often try to build embankment to protect the most populated areas of the city, but levee dykes constrict the water flow raising the water level upstream and increasing flood level both downstream and upstream. Flood banks increase the speed and depth of a river and when they break down, the river violently discharges its water on an unlucky suburb damaging buildings and killing people. In tropical countries, flooding can increase the number of diseases and infections as well as compromise the drinking water.

Floods are the most expensive weather hazard in the world, and because of the increasing number of people living in cities and the spreading of the urban landscape, the annual cost of flood damages has increased tenfold since 1930.

Predicting floods is mainly about monitoring weather and knowing the soil properties. A saturated soil will likely cause floods during the next generous rainfall. Mitigating flood involves freeing the ground from its armor of concrete and letting the soil absorb the water. It’s also possible to build dykes to deviate the water from important places, but as mention before it’s risky.

Photo by jim gade on Unsplash

Windy cyclones typhoons and hurricanes

First of all, typhoons, hurricanes and cyclones are all the same thing. These three words only have different histories and were originated from different cultures.

A cyclone is a massive tropical rotating low pressure system converting heat from warm oceans and humid air into strong winds, waves and precipitation. A cyclone is like a pit attracting all surrounding objects into it, the pit is the low pressure area and the objects are air flows.

Cyclones form on vast and warm masses of sea water. Then, weak winds moving in the same direction as the storm formation will facilitate the storm growth. Moreover, the Coriolis force gives its rotation direction as well as more energy to the storm. The Coriolis force is an inertial force inherited from the rotation of the Earth. Storms need all these conditions to exist, therefore they can form only between the equator and the tropics where the sea water is hot and the winds weak.

Once the cyclone has accumulated energy on the sea, it will move toward the continent blowing away the vegetation, people and buildings. A tropical storm speed is about 50 miles an hour while a real cyclone has a speed of 100 miles an hour. Threatening!

Photo by NASA on Unsplash

Human makes things worse

All these natural hazards are pretty threatening. And they are even more threatening when we look at how human beings have changed the environment. We have built cities putting a large number of people in it, we have fragmented and simplified the landscape, we have diverted and restrained rivers, we have built dams and created lakes.

Dams and their heavy reservoir can both produce earthquakes and landslides. Climate change disrupts the cycles of the water, increases the temperature and therefore the strength and frequency of cyclones, floods and tsunamis. It seems like only volcanoes are immune to human actions, and that’s for the best, because they are the most likely to end human existence over night.

We have technology to predict natural hazards, we are well organized. Still, we will never be invulnerable against Nature. Be ready to embrace the consequences of living with such a beautiful but unpredictable companion on Earth. Nature always bats last.