Climate changes and science behind the movie “The day after tomorrow”

Scene from the motion picture “The day after”. Credit: Twentieth Century Fox.

Can recent times of heat, cold, drought and floods be compared to the changes that happened in the past? How will natural cycles interact with the environmental alterations caused by humankind in the future? What is the probability of an extreme climate event occur, like in the movie “The day after tomorrow” (2005), directed by Roland Emmerich, that shows the dramatic effects of global climate changes?

The movie seems to focus mainly on the climate event known as “Nonlinear response of North Atlantic thermohaline circulation (THC)”. Consolidated information about this kind of event were already published by the Third Assessment Report (click here to read it) of the Intergovernmental Panel on Climate Change (IPCC).

“Non-linear response of the North Atlantic Ocean Thermohaline circulation (THC)”. Credit:

The worldwide ocean circulation, also known as “conveyor belt”, transports heat and influences local climate patterns. One of the components of this system is the Atlantic Ocean current, subject of the movie.  The warm surface currents flow to the North. The heat loss and evaporation on the surface make the temperature decrease and enhances the water density and salinity.  In the North Atlantic, the dense water sinks into the Labrador and Greenland seas until the deep-sea convection area and flows back towards South as deep waters.

The North Atlantic THC can, then, decrease the current speed or even collapse due to climate changes.  These events are found in paleoclimate records, being, therefore, plausible.  The consequences for ecosystems can be serious. The full stop could lead to a stagnated deep sea. This shutdown (interruption of the current) of the ocean current could also represent a big change on the amount of heat and on the climate in the North Hemisphere, shown in some scenes from the movie.

There are simulations that suggest that global warming in the next 100 years can lead to a collapse of the THC decades to centuries later, which would lead, inevitably, to major effects on future generations. This is considered one of the climate change tipping points, an irreversible impact.

Credit: Donald A. Brown – Scholar In Residence and Professor
Widener University School Of Law

When the movie starts, it is possible to see that the lecturer scientist talks about the same simulations when he says that his predictions were for a far future, just like those scientific documents available at that time. Hence, the shutdown occurred and led to a sudden reversion on the heating trend in the areas showed since the beginning of the movie. Neither the probability and the moment of a great change on the ocean circulation, nor its impacts can, yet, be assuredly foreseen. Nevertheless, this event presents a realistic and significant risk, in great part irreversible for hundreds of years and the beginning of it could be relatively abrupt.

Highlights of the movie as a legacy to present and future generations

The film develops in an interesting way when it comes to the distinct resilience of the characters and to the effects of the predicted tragedy in different social groups. For instance, there is a homeless man that appears many times, to point out and teach a lesson on the strong resilience that resides within those who face serious adversities on daily bases. This man starts tutoring the others as to how to behave to endure the cold, which is seen when he suggests for them not to burn all paper. His experience as a street dweller has taught him that the paper from the library books will be crucial to warm up the body and protect from the cold that was about to come and stay for long.

Some fiction situations are included in the movie touching the viewer who becomes aware and fears for the present and future generations, doubting how able we are to understand and deal with this problem. Again, at the beginning of the movie, there is the scene of the lecture given by the main character (speaker scientist) to a group of representatives from different countries. Some politicians react with the argument that is financially impossible to deal with this “not proven” problem. The movie depicts these conflicts involving economy, science and politics in many different moments.

The tragedy foretold in the movie about the need to displace entire populations from the North of the USA and from Europe, besides some from parts of Asia, is highlighted very well. It shows that the costs to prevent are always much lower than the costs needed to deal with the problem when it is already an existing fact. The film also emphasizes a recurrent problem involving minority groups of skeptics around the world and climate science deniers.

At the time the film was released, these groups managed to launch defamatory campaigns towards scientists, with funds received from fossil fuel companies against scientific evidences of the increase on global average temperature on the earth’s surface, and its impacts.  Nowadays, fifteen years later, this type of action to slander science has become more elaborated and faster.

These questions related to global climate changes have not been totally answered yet, but most studies have been pointing out to the need of articulation amongst the leaders of several countries towards adopting caution measurements regarding the subject. The studies have originated the United Nations Framework Convention on Climate Change (UNFCCC), in 1992.

The UNFCCC is accountable for the climate international policy, which resulted in many agreements such as the Kyoto Protocol, in 1997, and the Paris Agreement, in 2015. Annually, representatives of the signatory countries meet at the Conference of Parties (COPs). The last conference, COP25, took place in Madrid, 2019.

Credit: Donald A. Brown – Scholar In Residence and Professor
Widener University School Of Law

The expression “precautionary investment” is applied to the caution approach to be adopted when dealing with the problem, despite the uncertainties, especially when considering the risk of catastrophic consequences.  The temperature elevation on the planet and its relation with anthropogenic causes (caused by humankind), (see picture that follows) presents evidence, according to many studies with data from the last 100 years, the last 1000 years and the last one million years of the Earth’s climate, consolidated on the reports of the  Intergovernmental Panel on Climate Change –(IPCC).

Credit: IPCC 2007.

The graph illustrates the contribution of humankind to global warming. The black line is the “observed” which is measured, verified by measuring instruments. The natural effects alone (blue areas) do not explain the behavior of the average temperature on the earth surface (black line). The blue area represents the modeling of the participation of natural effects only, on the average temperature of the earth surface. The pink area on the graphs represents models using both natural and anthropogenic effects. One can notice that the pink area behaves similarly to the black line, which represents measured aspects.

Scientific climate measurements appear in the movie sometimes, as for example, when the ocean temperature parameters measuring buoys appear, right at the beginning of the movie. It seems like one of the buoys had had problems, and it was showing an abrupt cooling. This is shown on the dialogue between the man that represents a British scientist from the Hadley Center, and the researchers from the Monitoring and Observation Center, who work with the data collected by the buoys. But, actually, it was not a problem with the equipment. All the other buoys also started to show an abrupt drop on the temperature.

And so the adventure of an extreme climate event begins, where a huge area gets frozen, just like the mammoth suggests on the scene of youngsters visiting the Museum of Natural History of Washington.  They notice that the mammoth standing position shows a natural move, which was part of its routine, and the group of young people make comments about how abruptly the animal was caught off guard by a freezing event. Little did they imagine the same was about to happen to themselves. Another example of historic climate parameters measurements shown by the movie is the ice core. There is a thrilling scene, in which the main character escapes a disaster while working with his research colleagues. They seem to wear uniforms of the National Oceanic and Atmospheric Administration – US Department of Commerce (NOAA).

Credit: NOAA.

This disaster happens during an experiment expedition to drill holes into thick ice layers in order to analyze the composition of the atmosphere in ancient times. This experiment is the basis for many others as well as the source of information regarding global climate.  It is important to stress the fact that the crack on the frozen ground showed on the movie has no relation with the drills of the experiment, but with the extreme event part of the plot, which it is depicted later on.

The IPCC scientific panel helps the UNFCCC on its decision making process. The first IPCC report was published in 1990, the second in 1995, the third in 2001, the fourth in 2007, the fifth in 2014 and the sixth will be finished in 2021. The three main IPCC Groups are Group I – Climate Science; Group II – Vulnerability, Impacts e Adaptation and Group III – Mitigation. Group I addresses Atmosphere Science and its interaction with the oceans and the Earth surface, aiming to identify and register climate global changes and its causes. Group II relates to studies on vulnerability to global climate change, its impacts, and the adaptations proposals to these impacts. Group III – Mitigation relates to studies on how to minimize the problems related to global climate changes.

Participants on a press conference to release the Intergovernmental Panel n Climate Change Report, including the UN Secretary-General (center) Ban Ki Moon and the IPCC President, Rajendra Pachauri. Kopenhagen, Danemark (November 2, 2014). Credit: Amanda Voisard/UN Photo.

Most studies focus on the reduction on the concentration of greenhouse gases in the atmosphere, especially carbon dioxide. This concentration of gases has been worsening by the world economy model since the Industrial Revolution in the XVIII century based on coal burning and later on, the use of petroleum (fuel) and its derivatives. A smaller number of researches are related to technologies that do not solve the problems related to anthropogenic sources of greenhouse gas emissions.

These researches evolve around large-scale mitigation proposals that go by the knickname of Geo-engineering, such as the ocean fertilization, Solar Radiation Management (SRM), sun light reflection, and artificial volcanos for the artificial cooling of the atmosphere, besides Carbon Capture and Storage (CCS). CCS involves geological storage (there are pilot researches on oil wells, coalmines and salt-water aquifers), and chemical and biological storage. All these proposals pursue great impacts, not yet completely measured, and do not involve changes on the causes of the problem.

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Brief History of the Greenhouse Gas Effects as a Global Issue

Jean Baptiste Joseph Fourier noticed the greenhouse effect for the first time during the French Revolution, in the XVIII century. He was the first person to conceive the planet Earth as a giant greenhouse, enabling plants and animals to live and thrive on the Earth’s surface. In 1896, Svante Arrhenius designed a model to study the influence of the carbon dioxide present in the atmosphere, on the temperature of the Earth. Arrhenius used the measurements of spectral thermal emission of the lunar surface, performed by Samuel P. Langley, to calculate the H2O and CO2 absorption coefficients, which were key to design the model he conceived.

The causes related to the Ice Age, current subject of study in some research centers, as the Stockholm Physics Society, was one of the questions Arrhenius’ quests. His experiments were successful and the results have been proved right by modern computer simulations. The greenhouse gases as we call nowadays were named “hothouse gases” by Arrhenius.

Some authors consider the Atmosphere Science as the most complete science to the comprehension of the Earth System concept. It comprises the history of the planet formation and its atmosphere evolution, besides biology, geology, and hydrology.  The prevailing view amongst scientists that study climate is that there is an ongoing global warming which has been caused, in part, by anthropic gases emissions, such as carbon dioxide, that traps heat and, when in excess, results in greenhouse gas effect.

However, in spite of being just a few, there are still some scientific questions regarding the matter. Experts disagree, among other things, with respect to the existence and importance of the increment on the referred global warming phenomenon. For instance, some researchers from the Lamont-Doherty Earth Observatory at Columbia University state that century-long cold peaks, similar to the Little Ice Age, have been occurring regularly, around every 1450 or 1500 years. They also state that by the end of the XIX century and beginning of the XX century, the temperature started rising again at around 0,46 degrees, which suggests the world is at the beginning of a century-long natural warming cycle.  Massachusetts Woods Hole Oceanographic Institute researchers, on the contrary, state that these variations are not so simple to be determined. In other words, the variations are not periodically precise, making it impossible to know exactly where we are in these periods.

Another research group, the National Oceanic and Atmospheric Administration’s Geophysical Data Center, in Colorado, states that, even if the world is at the beginning of a natural warming phenomenon, any gas emissions that can cause greenhouse effect must be seen as an additional problem, knowing that it could lead to an even higher rising on the temperatures. Therefore, prevention approaches should be considered.

The discussions regarding the causes of climate global warming involve, yet, some doubts that incur political issues. Besides questions related to the responsibility of each country or groups of countries, one of the most important ones relates to the difference in the emphasis given to the causes.  Some studies, carried mainly in developed countries, emphasize that the greenhouse gas emissions that have happened in recent times are increasing in developing countries, and this should be the focal point.

Other studies emphasize the importance of these gases concentration to the understanding of how the climate is warming, which involves a history analysis of these countries economic development. These gases stay in the atmosphere for many years. For instance, carbon dioxide stays, on average, 140 years in the atmosphere.

However, according to John H. Seinfeld and Spyros N. Pandis, this time is of 200 years, an estimation that combines the gas lifespan in the atmosphere, biosphere and in the oceans. Global climate changes involve both natural and anthropogenic causes, which is internationally debatable since the 1980s. The scientific uncertainties and different views on the causes and on a real existence of a global warming phenomenon have been subjects to important debates all over the world. However, the relation between climate global warming and anthropic activities has been increasingly recognized throughout time, mainly due to the use of power sources based on fossil fuel.

Therefore, there is an increase on society requests for social and economic development aligned with greenhouse gases reduction and use of alternative power sources. However, there is a period of time required for transitioning from the use of fossil fuels to the use of new power sources. Aligning economic development with lower carbon emissions takes on a complex group of actors, such as governments, public and private companies, civilians, academics and non-governmental institutions.

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A 99% of the atmosphere composition is predominantly of nitrogen (N2), oxygen (O2) and argon (Ar). If there were only these three gases on the atmosphere, the average temperature on Earth would be lower than zero Celsius degree and the oceans would be frozen.  However, the presence of other gases (1%) avoids the transmission of part of the heat from the atmosphere to the space, increasing its temperature. This natural control of the Earth’s temperature is known as the greenhouse effect.

The gases responsible for this effect are the greenhouse gases – GHG. Their compounds are mostly nature molecules found in the atmosphere. The most important ones are carbon dioxide (CO2), water vapor (H2O), methane (CH4), ozone (O3) and nitrous oxide (N2O). The higher the concentration of GHG, the higher is the heat absorption and, hence, the atmosphere warming. Greenhouse effect has existed for a billion years, making life possible on the surface of the Earth, as it is known.  If there were no natural greenhouse effect, the average temperature on Earth would be around -18o C. However, the average global temperature on the surface of the Earth under the greenhouse effect is around 15o C.

Water vapor is the gas accountable for most of the greenhouse effect due to its abundance. The second one is carbon dioxide, CO2, which is naturally emitted to the atmosphere (for example, it has been naturally emitted by volcanos throughout the history of the planet Earth) and non-naturally – anthropogenic. Greenhouse effect has started to alarm the scientific community because the fast increase on the concentrations of GHG due to the anthropogenic emissions that have been intensifying the greenhouse effect.

The increase on the concentration of CO2 in the atmosphere coincides with the industrialization of society and there are some good evidences to indicate that the increase is caused by the growing emissions of CO2 resulting from human activities. The current concentrations are higher than in the last 420.000 years and probably higher than in the last  20 million years.

The most relevant contributor to the increase in the quantities of atmospheric CO2 is the fossil fuel burning (for example, combustion engines) and the change on the use of land, currently in the tropics, and in the XVIII and IXX centuries in the countries of the north hemisphere. In the last 150 years, the concentrations of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) increased. Besides this, artificial gases started intensifying the greenhouse effect:  hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), Sulphur hexafluoride (SF6), chlorofluorocarbons (CFCs) and hydro chlorofluorocarbons (HCHFCs) (IPCC, 1996).

In response to the several scientific evidences on the possibility of global warming, the United Nations Environment Program (PNUMA) and the World Meteorological Organization (WMO) created the Intergovernmental Panel on Climate Change – IPCC in 1988. The IPCC is responsible for providing information about Science, impacts and economy, besides mitigation and adaptation options related to the climate change. The IPCC work represents a common ground of the climate change scientific community and it is recognized as the most reliable source of information about climate change and its causes. Several Science academies worldwide endorse the methods used by IPCC to reach a consensus.

In the upcomig years, regional climate changes can happen, including high temperatures, warmer winters, an exacerbated average global hydrologic cycle, changes on biodiversity and on the carbon cycle, increase on the average sea level due to the thermal expansion of the oceans and glaciers and ice blocks melting.  There are some issues on climate change related to the regional impact scale and to the consequences to society.  However, the climate changes implications and mitigations are clear in terms of consumption and development, since industrialization happened based on fossil fuel burning. The theme is mandatorily a global theme, once the atmosphere is a common good, the impacts reach the entire planet and the access to vital resources as water and energy become scarce.

Credit: Intergovernmental Panel on Climate Change –(IPCC)/Donald A. Brown – Scholar In Residence and Professor Widener University School Of Law. Professor´s blog:

Global warming and melting glaciers

Water represents 71% of the Earth’s surface, with approximately 97,5% of salt water and 2,5% of fresh water. Fresh water is found mostly in solid-state – around 2/3 in glaciers and polar ice caps. The remaining 1/3 of fresh water, in liquid-state, is mostly found underground, and around 0,26% of all the fresh water in rivers, lakes, and not so deep water tables.

Global warming has already lead to a reduction on the amount of frozen fresh water. Researchers from the World Glacier Monitoring Service, in Switzerland, for example, have already registered a decrease on the size of the Antarctic continent, which has happened at a regular rate the past years. However, a reduction on the amount of ice is more evident in the Artic.

Climate change natural and anthropogenic factors

It is important to separate the climate change natural factors from the anthropogenic ones and pursue solutions that are compatible with their causes. Currently, the scientific concern with the impacts of global warming involves wide and complex aspects, such as the change on the salinity and temperature of the oceans, impacts on biodiversity and elevation on the sea levels.

Another type of concern regards the indirect effects, as the great amount of carbon within the frozen areas that tend to be released in gas-state through melting processes. These gases emissions would result in an additional increase on the concentration of carbon in the atmosphere.

Artic Polar Cap Shrinkage

Credit: Book “An Inconveniente Truth”, by Al Gore.

 Warming trends in Antarctica (1957-2006)

Credit: Book “An Inconveniente Truth”, by Al Gore.

It is important to highlight that only in cases of melting of continental areas, there would be a rise in sea level. In case of the ice blocks melting, that are not in the continents, like the icebergs for instance, there is no impact on the elevation of the sea level. It is imperative to separate climate changes natural causes from anthropogenic causes, in order to propose the right actions towards correcting the problems. Besides the climate changes originated from humankind actions, there are climate changes caused by nature itself that can be aggravated by human actions. There are four types of important natural phenomenon related to global climate changes according to “Coleção Explorando o Ensino Volume 13. Mudanças Climáticas. Brasília 2009, issued by INPE/AEB- Agência Espacial Brasileira”:

 i.Changes in the configuration of the continents

In 1912, Alfred Lothar Wegener published a paper suggesting that 200 million years ago all the continents were united in one big land mass called Pangea and surrounded by one and only ocean called Panthalassa. According to his theory, as time went by, alterations happened to this continent mass leading to what there is today in terms of blocks of continents, which are still slowly moving. In this process, as the continents took different locations on the Earth’s surface, the distribution of the climate zones and the ocean circulation also changed and became different from what they were in the past. These variations represent thousands of years of changes.

ii.The Stellar Evolution Theories

Some stellar evolution theories suggest that the sun were “weaker” in the first billion years of the Earth’s history. However, the planet was not cold, for there was, possibly, a strong greenhouse effect that would compensate and reduce the solar radiation.

 iii.The Milankovitch Theory

Variations on the Earth’s orbit and subsequent variations on the amount of heat reaching the planet influenced climate changes in the past. Astronomic causes trigger variation on the solar radiation, causing variations on the amount of ice, and therefore, on the global temperature.

The mathematic climate theory, based on seasonal and latitudinal variations on the solar radiation that reaches the Earth is known as the Milankovitch Theory, formulated by a Serbian, Milutin Milankovitch, at the beginning of the XX century. Milankovitch’s theory is based on cyclic variations of three elements that cause changes on the amount of solar energy that reaches the Earth. They are: precession; changes on obliquity; eccentricity variation.


Alterations in the orientation of the Earth’s rotational axis in relation to the Sun modify the months of the seasons (summer, autumn, winter and spring) on a specific hemisphere. This process takes around 20 thousand years.

Changes on Obliquity

It is about changes on the tilt of the Earth’s rotational axis. When the axial tilt is bigger, winter seasons are colder and summer seasons are hotter. When the tilt is smaller, the seasons are milder. Currently, the tilt is 23,5o, but it can vary from 21,5 to 24,5o. The time required for the Earth’s axial tilt to vary is around 40 thousand years.

Eccentricity Variation

The eccentricity is related to the Earth’s orbit in relation to the Sun. The orbit can be more “elliptical” or more “rounded”. When it is more on the elliptical side, the difference in insolation between January and July is higher. The time need for the eccentricity variation is around 100 thousand years.

iv.The aerosols

The aerosols are suspended particles in the atmosphere, such as dust or pollen. For the most part, aerosols are originated in nature, mainly by volcanos, natural vegetation burnings, and by the wind blowing on the surface of the sea and on areas of naked soil. The aerosols have a very important role on the energy balance, once they can absorb and reflect radiation. Due to their high importance on the clouds formation, the aerosols also influence indirectly the energy balance in the atmosphere. That happens because the clouds are highly efficient as bodies that reflect radiation back into the space. Clouds that are formed in high concentrations of aerosols tend to present a bigger number of drops, and, consequently, smaller ones. They reflect solar radiation more efficiently than the clouds that are formed by bigger drops and in small number.

Volcano eruptions yield the biggest impacts related to aerosols in the atmosphere, sending out billions of tons of aerosols to the globe, every year. In some cases, these aerosols reach very high layers, and can remain there for long periods. The Pinatubo volcano, in the Philippines released a great amount of Sulphur in the atmosphere in 1991, which was eventually, converted into sulfate aerosols. Because of the characteristics of this type of aerosol, it is estimated that there was a drop on the global average temperature of about 0,6°C,  2 years after the volcano started going into activity.

Alterations on the cycles of carbon and water (based on INPE/AEB, 2009)

One of the arising problems from melting the ice on the planet, and recently observed, is the alteration on the carbon and water cycles, besides other important cycles for the Earth system balance. The cycles of carbon and water allow us to breath and allow our life to exist on the planet Earth. The correlation between the water cycle and the carbon cycle enables the production of oxygen (O2): [CO2 + H2O + solar energy = CH2O + O2]

Until before the Industrial Revolution, the carbon cycle was in balance. The carbon that was absorbed by the soil and ocean was equal to what was released into the atmosphere. With the industrialization and fossil fuel burning intensification due to human activities, the release of carbon gas became higher than nature absorption capacity. That means, the carbon that was stored in the soil and in the oceans during thousands of years starts to be released into de atmosphere by human activity, in a short period of time, making it impossible for the natural cycle to bring carbon back into its reservoirs.

The carbon cycle can be divided in two parts, which are the land cycle and the ocean cycle. In the land cycle, the plants take carbon gas from the atmosphere through photosynthesis.  The plant for its own maintenance uses part of this carbon, and it is incorporated into the plant’s body (leaves, branches, trunks and roots). The rest is emitted into the atmosphere as carbon gas.

The forests are of major importance to the water and carbon cycles. The changes on the use of soil after the Industrial Revolution regard alterations due to human activity, which have greatly reduced the planet green coverage. Between 1700 and 1990, large forest areas were vanished from all over the globe to fulfil demands of ongoing industrialization.

The following illustration brings a comparison of the forest coverage on the globe in 1700 and in 1990, 290 years later. The deforested area in this period is concentrated in the so-called “developed” countries. The forests and other biomes are better preserved, according to image, in the “developing countries”. However, after 1990, these countries showed fast and concerning deforestation, following harmful standards of production and consumption.  The areas in red represent the areas that were deforested in the specified period, for agriculture purposes. The brown/beige color represents deforested areas for pasture.

Lecture, “Ethical issues entailed by the forest agenda in the Bali Roadmap”, in Poznan, Poland. By Maria Silvia Muylaert de Araujo. Credit: IVIG/COPPE/UFRJ..

The carbon ocean cycle happens through exchanges of carbon gas between the atmosphere and the oceans, by a chemical process called “diffusion”. When the temperature of the ocean is low, carbon gas diffuses from the atmosphere into the ocean. In addition, when the temperature is high, carbon gas is released from the ocean into the atmosphere.

This feature is opposite to the land carbon cycle, in which the highest rates of carbon dioxide sequestration from the atmosphere are in the forests and in warmer tropical areas. As for the carbon in the oceans, the highest rates of sequestration are in the cold seas of temperate areas.

Once on the surface of the ocean, the sequestrated carbon can be slowly transferred by gravity and other currents to deeper layers. When in the ocean, the carbon residence time varies from decades to millenniums, which makes the oceans the biggest reservoirs of carbon on the planet.

Marine Cycle


 The environmental and social economic impacts of climate change

The climate scenarios conceived for this century show that the planet average temperature will keep going up and the projections are indicative of a bigger number of hot days and heat waves in all continents. A possible increase on the frequency and intensity of precipitation in several regions can occur, especially in tropical regions. Some projections talk about widespread droughts in continental areas during summer. Many models show an increase on the temperature of the water surface in the Equatorial Pacific Ocean, which suggests a future situation of an almost continuous El Niño.

The climate change caused by the warming of the Earth can have global devastating effects. Tropical islands and glaciers in the Alps can disappear. Floods and droughts will occur more frequently and the agriculture productivity will decrease. An increase on the occurrence and intensification of extreme climate events is expected, alterations on populations and on the geographic availability of mammals, invertebrate, reptiles, amphibious and insects. In addition, there are predictions that alterations on the climate will affect wind patterns as well as clouds coverage patterns.

The rise of the sea level can affect the provision of fresh water to the coastal aquifers that can become saline by the intrusion of seawater.  The economic meaning of the average sea level rise is considerable. There can be consequences to fishing, agriculture, sailing, effluents discharge, coastal protection, biological and biodiversity productivity. The oceans play a vital role on the water cycle. They function as regulators to the global climate by the fluxes between water, the land atmosphere and vegetation.  The oceans take part in the CO2 flux, absorbing around 30% of the CO2 from anthropic sources.

Credit: Nasa Climate Kids.

Climate changes, including melting, can, besides leading to changes on the temperature of the sea, lead to alterations on the ocean circulation patterns, on the vertical mix of the water, and on the waves patterns. Consequently, there can be impacts on the ocean biological production, on the ecological structure in some regions and on the availability of nutrients.

It is important to highlight that the majority of greenhouse gases have a long life in the atmosphere until they are removed. Global climate models show that, even if these gases concentrations in the atmosphere were kept constant at the values they currently present, the temperatures would keep on rising for over 200 years and the sea level, for over a millennium.

It is also known that global warming will cause the polar caps melting, contributing to the average rise in sea level and flooding of lower areas. Evaporation on the equatorial regions will rise and, consequently, hurricanes and tropical storms must be more active. Besides that, it is expected that the occurrence of tropical diseases such as malaria, dengue and yellow fever will also grow.

In the movie “The day after tomorrow”, many extreme events are simultaneously depicted, such as a very impacting scene that takes place in California where various hurricanes strike and there is destruction of many areas. A sudden frozen event of helicopters, people, and of entire ecosystems. There is a very interesting parallel stablished between mammoths from historical times that appears on the Museum of Natural History scene.  There is also a scene showing a ship sailing in front of the public library where many people are sheltered. This situation demonstrate a possible rupture of damps and the rise of the water that starts flooding the city.

Coastal and Riverside ecosystems in areas subjected to tides influence can be deeply altered, if a fast sea rise happens. Agriculture and hydroelectricity generation could also be affected by changes on the rains distributions, long periods of drought, or impacts from melting areas.

More than 24 million of km3 of frozen water are on the Antarctic, Greenland, Artic, mountains and in their frozen soils. This water represents less than 2% of the total water on the planet, but it needs to keep the necessary balance, so the planet continues functioning, as we know. Many animal species, like bears, seals and penguins have the ice as their natural habitat. Wales get food from the frozen seas on the Poles. Life blossoms in the ice. Ice balances out life on the planet, but global warming melts the ice, destroys habitats and species. Ice reflects the solar rays of light and, without it, greenhouse effect increases, in a vicious cycle, where less ice induces more heat and more heat reduces ice.

Seawater expands with heat and takes up more space. The higher the temperature, the bigger is the risk of continental blocks slipping into the ocean, rising the sea level. Entire cities located on the coastal area can be dramatically affected.

Freshwater originated from defrosting processes, when mixed to salty water can change the temperature and patterns of the circulation in the oceans. The North mild temperature brought by sea currents can be strongly decreased. Melting can cause emission of greenhouse gases that have been stored for long periods under the ice layers, worsening global warming.

Natural disasters as the ones caused by tsunamis leave behind a big number of missing and dead people, besides countless social economic and environmental damages, emphasizing the current existing vulnerability to deal with catastrophes. It is worth highlighting that many natural events like tsunamis do not have a cause and effect relation with global climate changes, but they expose the vulnerability of a system to respond to disasters.

Credit: Donald A. Brown – Scholar In Residence and Professor
Widener University School Of Law

It is important to involve all social sectors on the quest for proposals on how to respond to impacts caused by global climate change. The most effective way to face natural disasters impacts is the adoption of preventive measures.

Correctional measures, as engineering constructions, are usually more expensive and palliative measures. Devastating Hurricane Katrina, for example, in New Orleans, USA, was caused by the rupture of damps that had been built to resist hurricanes of lower categories compared to Katrina’s.

Amongst other actions, it is vital to stop global warming and limit the increase on the average global temperature on the surface of Earth to 2º C until 2100. This limit value is stablished in relation to the time before the Industrial Revolution. The rains originated from the evaporation on the seas, as part of the water natural cycle, ongoing for billions of years, maintain the body of the rivers, lakes and water tables.

Increase on the rainfall volume and saltwater intrusion

The offer of fresh water in the coastal aquifers can be affected by an increase on the frequency of rainfall and on the sea level rise, causing salinization due to the intrusion of salt water. Salt-water moving inwards towards estuaries can lead to the need of fresh water transfer to inland areas, far from the coast, implying consequences such as water availability, its cost, coastal agriculture, sewage and sanitation systems. Some storms in in the world  have been identified as a result of extreme climate events, like storms that happened in Santa Catarina, Brazil, in the 2000s.

Finally, the movie alerts to a very important ethical dimension of the global climate change, regarding society as a whole. The final part of the movie is very ludic, showing the importance of opening the Mexican borders for the Americans.

The boarders were opened to receive the Americans, who managed to be safe from the abrupt cold, and searched, on foot, for warmer areas on the planet. By showing this, the movie brings a narrative of inversion on the current migration stream, with uncountable problems related to social hosting and rejection in the US. It implies some type of pay back with refinements of dignity, pride, and a message of sympathy and humanity, above all.

The movie addresses part of the climate science, on a fictional way, which is part of scientific studies and for which we must be prepared. The events brought up in the plot have already been found in Paleo climatic records, proving to be reasonable. The movie shows that global warming confrontation involves much effort from all, and that a precautionary attitude is necessary for that purpose.

Source: Article originally published in Portuguese on the website Revista Intertelas.
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Maria Silvia Muylaert de Araujo 
FAU/UFRJ Architect/Urbanist.  IPPUR/UFRJ MSc. Institute for Housing and Urban Development Studies Post-graduate, IHS, Rotterdam, Holland. PPE/COPPE/UFRJ DSc. L.A. IPCC/AR5 / GT III Ch. 4, 2014. L.A.IPCC/AR6/WG2/Ch18 (to be concluded in 2021).

Special thanks to Donald A. Brown, Scholar In Residence and Professor at Widener University School of Law, Part-time Professor at Nanjing University Of Information Science and Technology, for the material provided from his lecture in November 2020

To access Professor Donald A. Brown’s lecture material, click on the following link (it may take some minutes to download the file): Civilization’s Most Challenging Ethical Problem Climate Change, by Professor Donald A. Brown – Professor´s blog:

English translator: Daniele Moraes Electo de Paiva
Video/Photos editing and research: Alessandra Scangarelli Brites


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