HOW TO PLAN CITIES TO COPE WITH EXTREME WEATHER EVENTS

Fernando Alcoforado*

Abstract: This article aims to present what and how to do to promote cities planning capable of facing extreme climate events.

Keywords: Global warming; Global climate change; Causes of extreme weather events; Impacts of extreme weather events on cities; How to prepare cities against extreme weather events; Cities planning required to face extreme weather events.

1. Introduction

This article aims to present what and how to do to promote cities planning capable of facing extreme weather events. The occurrence of floods in cities in several countries around the world has been recurring. There is a drastic change in the Earth's climate thanks to global warming, which is contributing to the occurrence of floods in cities that are recurring in an increasingly catastrophic way in their effects. The floods that devastated some cities in western and southern Germany, Henan in China and London in England in 2021 demonstrate the vulnerability of highly populated areas to catastrophic flooding [2]. ?

The catastrophic floods that swept through Europe and China recently are a wake-up call that stronger dams, dikes and drainage systems are as urgent as long-term climate change prevention measures because once-rare weather events are increasingly increasingly common. Drastic cuts in greenhouse gas emissions are certainly necessary to combat climate change and will not cool the planet in the short to medium term. However, until the Earth's climate stabilizes, each country will need to prepare its cities to face extreme climate events [2]. In many countries, flood-prone rivers need to be carefully managed. Defenses such as dikes, reservoirs and dams need to be used to prevent rivers from overflowing their banks.

Governments need to admit that the infrastructure they have built in the past for cities, even in more recent times, is vulnerable to these extreme weather events. There are solutions that can be adopted by governments to protect cities affected by extreme weather events as a result of global warming and the resulting global climate change, which tends to be catastrophic. To deal with the increasingly frequent floods, governments need to act simultaneously in three directions: the first is to combat global climate change; the second consists of preparing cities to face extreme climate events and, the third, consists of implementing a sustainable society at national and global levels [2].

2. Causes of extreme weather events

Extreme weather events result from global warming. Global warming is a far-reaching climate phenomenon - an increase in the Earth's average surface temperature that has been occurring over the past 150 years. The IPCC (Intergovernmental Panel on Climate Change), established by the UN (United Nations), says that much of the warming observed on the planet is due to the increase in the greenhouse effect and there is strong evidence that global warming is due to human activity. Many meteorologists and climatologists consider it proven that human action is actually influencing the occurrence of the phenomenon. There is no doubt that human activity on Earth causes changes in the environment in which we live [1]. Many scientists consider that the increase in the planet's average temperature results from the greenhouse effect, which is responsible for the severe effects of climate change, resulting in inclement rainfall and consequent floods.

Global warming and the consequent global climate change, which tends to worsen, are contributing to the occurrence of intense rains and floods across the planet. Due to global warming, the atmosphere retains more moisture, which means that when rain clouds become dense, more water is released. By the end of the 21st century, storms of great magnitude will be more frequent, according to a study published by the journal Geophysical Research Letters, using computer simulations [2]. Floods are caused by many factors such as heavy rainfall, strong winds on the water, unusually high tides, tsunamis or dam failures, rising levels of retention ponds or other structures that contain water. Periodic flooding occurs in many rivers, forming a surrounding region known as the floodplain. During times of rain or snow, some of the water is retained in ponds or in the soil, others are absorbed by grass and vegetation, some evaporate and the remainder travels over the land as surface runoff [5].

Floods occur when lakes, riverbeds, soil and vegetation cannot absorb all the water. Water then escapes from the land in quantities that cannot be transported to stream channels or retained in natural ponds, lakes and artificial reservoirs. About 30% of all rainfall is in the form of small runoffs – some of which can be increased by water from any melted snow where it exists. River flooding is usually caused by heavy rains and sometimes without warning, they are called flash floods. Flash floods usually result from heavy rainfall in a relatively small area, or if the area was already saturated with previous precipitation [5].

Severe winds over water are another cause of flooding. Even when rain is relatively light, the shores of lakes and bays can be flooded as a result of strong winds such as during hurricanes that blow water into coastal areas. Another cause is the unusually high tides that sometimes occur in coastal areas when they are inundated by unusually high tides, especially when compounded by strong winds and storm surges [5]. Many of these environmental impacts result from the unsustainability of society's current development model. The unsustainability of society's current development model stems from the fact that it is responsible for the rapid increase in global temperatures, the depletion of the planet's natural resources and the rise in sea levels on a greater scale in the 21st century than in 10,000 years ago since the last ice age [4].

3. The impacts of extreme weather events on cities

Floods cause many impacts. They damage property and endanger the lives of humans and other living beings. Rapid water runoff causes soil erosion and concomitant sediment deposition in several locations. Fish spawning grounds and other wildlife habitats can become polluted or completely destroyed. Some high and prolonged floods can compromise vehicle traffic in areas that do not have elevated roads. Floods can interfere with drainage and the economic use of land, such as interfering with agriculture. Structural damage can occur to bridge piers, sewer systems and other structures in the flood area. Water navigation and hydroelectric power are often hampered. Financial losses due to flooding are typically millions of dollars each year [5].

An important impact resulting from flash flooding is landslides. A landslide is a geological and climatological phenomenon that includes a wide spectrum of ground movements, such as rockfalls, depth slides and debris flows. Landslide is actually just one category of so-called mass movements, which involves the detachment and transport of soil or slope rock material. Three influencing factors can be considered in the occurrence of landslides [2]:

? Type of soil with its constitution, granulometry and level of cohesion;

? Soil slope that defines the angle of repose, according to the weight of the layers, granulometry and level of cohesion;

? Water-soaked soil that contributes to increasing the weight of specific layers, reducing the level of cohesion and friction, also responsible for the consistency of the soil and lubricating the sliding surfaces [2].

To prevent soil sliding, one of the measures is to ensure that the water that runs down the slopes of the mountains drains and loses speed or infiltrates the soil through the use of vegetation. Another, safer, measure is to build terraces in the form of steps to protect the soil from rainwater. Finally, you can use cable-stayed walls, which are robust walls made mainly with concrete and which, in parallel, require interventions in the ground to support the work [2]. Floods that occurred in many cities around the world reveal the incompetence and irresponsibility of public authorities in not planning the city to face extreme weather events. It is not necessary to demonstrate that flooding causes many extremely negative impacts.

Water-related disasters represent 90% of all disasters in number of people affected worldwide. Social and economic costs have increased in recent decades and, according to speakers at the High Level Panel on Water and Natural Disasters at the 8th World Water Forum, the trend will continue to increase if action is not taken to resolve the problem. By 2017, water-related natural disasters caused global losses of US$306 billion. Between 1980 and 2016, 90% of disasters are climate-related. In 2016, of global losses, 31% were due to storms, 32% attributed to flooding and 10% to extreme temperatures [2]. Floods are responsible for the deaths of almost twice as many people as tornadoes and hurricanes combined [2].

4. How to prepare cities against extreme weather events

To deal with extreme weather events in cities, flood control must be carried out. Flood control concerns all methods used to reduce or prevent the harmful effects of water action. Some of the common techniques used for flood control are the installation of rock berms to help with the stability of slopes to hold blocks, rock rip-raps or rock fill, sand bags, maintaining normal slopes with vegetation or applying cement. on soil with steeper slopes and drainage construction or expansion. Other methods include dikes, dams, retention or detention basins. After the 2005 Hurricane Katrina disaster in the United States, some areas prefer not to have levees as flood control. Communities chose to improve drainage structures with detention basins [6].

Some flood control methods have been practiced since ancient times. These methods include planting vegetation to retain excess water on slopes to reduce water flow and building alluviums (artificial channels to divert flood water), building dikes, dams, reservoirs or tanks to store extra water during periods of flooding In many countries, rivers subject to flooding are often carefully managed. Defenses such as dikes, reservoirs and dams are used to prevent rivers from overflowing their banks. A dam is one of the flood protection methods, which reduces the risk of flooding compared to other methods as it can help prevent damage. However, it is best to combine levees with other flood control methods to reduce the risk of a collapsed levee. When these defenses fail, emergency measures such as sandbags or portable inflatable tubes are used. Coastal flooding has been controlled in Europe and North America with defenses such as ocean walls or barrier islands which are long strips of sand usually parallel to the coast [6].

The engineering works that can prevent and mitigate the effects of flooding in cities are as follows: 1) Construction of large swimming pools, which are large underground water tanks to store water; 2) Mandatory placement of permeable drainage floors in huge parking lots in shopping malls, supermarkets and cinemas, to allow water infiltration into part of the soil, with the same action being taken for monuments and spaces around buildings; 3) Use of drains and gutters around all houses to divert rainwater to a reservoir or disposal area; 4) Maintenance, whenever possible, of some green areas so that water is absorbed by the soil; 5) Rectification of rivers and streams, construction of dams and canals on large rivers that extend their containment basins; 6) Meteorological monitoring of the city's climate to identify the occurrence of extreme events; and, 7) Implementation of a civil defense system that must be able to at least alert people and have a scheme to remove them from their homes in time with some belongings and accommodate them [6].

Taking care to avoid flooding in urban areas is: 1) keeping streets and sidewalks always clean; 2) clean and unclog drains and rainwater drainage; 3) keep rain channels free of tree branches and leaves to avoid clogging and, consequently, the return of water; 4) place garbage bags on the sidewalks only close to the moment the garbage collection truck arrives, preventing them from being pulled into the drain when it rains; 5) have a drainage pump on hand if flooding cannot be avoided; and 6) use Dutch and British flood-proof technology as a floating amphibious house that allows it to float in the same way as a boat [6].

Hydrology experts recommend that, to avoid flooding in urban areas, the following measures should be adopted: 1) Combating erosion by minimizing sedimentation of natural and constructed drainage through rigorous and extensive control of soil erosion and irregular disposal of urban waste and construction debris, as well as the expansion of river channels; 2) Combating soil sealing with the creation of domestic and commercial reservoirs, as well as the expansion of green areas; 3) Prohibition of traffic on avenues with large vehicle movements when nearby rivers overflow; 4) Implementation of avenues covered by vegetation so that, in cases of river or stream overflow, the water would be absorbed by the unpaved soil; 5) Construction of large swimming pools to receive rainwater and mini swimming pools in houses and buildings; 6) Investment in small and large streams in the urban center to receive the increase in water and act as containment barriers; 7) Review of occupied areas with continuous land use planning; and 8) Action and planning with the development of a plan to deal with the occurrence of floods, as well as extreme climate variations, and construction of reservoirs capable of storing billions of cubic meters of water and its use for non-potable purposes [6].

Correction and prevention measures to minimize damage caused by floods are classified, according to their nature, into structural and non-structural measures. Structural measures correspond to work that can be implemented to correct and/or prevent problems arising from flooding. Non-structural measures are those that seek to prevent and/or reduce the damage and consequences of floods, not through work, but through the introduction of standards, regulations and programs that aim, for example, to discipline the use and occupation of land, implementation of alert and population awareness systems [6].

Structural measures comprise engineering works, which can be characterized as intensive and extensive measures [6]. Intensive measures, depending on their purpose, can be of four types:

? Acceleration of outflow: pipelines and related works;

? Flow delay: reservoirs (retention basins), restoration of natural gutters;

? Flow diversion: bypass tunnels and diversion channels;

? Individual actions to make buildings flood-proof.

On the other hand, extensive measures correspond to small water storage in the basin, restoration of vegetation cover and control of soil erosion along the drainage basin [6].

Structural measures can create a sense of false security and even lead to the expansion of occupation of flood areas. Non-structural actions can be effective at lower costs and longer horizons, as well as seeking to discipline territorial occupation, people's behavior and economic activities [6].

Non-structural measures can be grouped as follows [6]:

? Actions to regulate land use and occupation;

? Environmental education focused on controlling diffuse pollution, erosion and waste;

? Flood insurance;

? Flood warning and forecast systems.

By delimiting areas subject to flooding depending on the risk, it is possible to establish zoning and the respective regulations for construction, or for possible individual protection works (such as the installation of floodgates, watertight doors and others) to be included in existing buildings. Likewise, some areas may be expropriated to be used as squares, parks, parking lots and other uses [6]. In certain cases where structural measures are technically or economically unfeasible (or even untimely), non-structural measures, such as warning systems, can reduce the expected damage in the short term, with small investments [6].

Issues related to structural and non-structural flood prevention measures were a prominent topic at the 2nd Asia-Pacific Water Summit in Chiang Mai. There is a wide gap between groups that prefer "structural" solutions to disaster management and those that prefer "structural" solutions to disaster management "non-structural". Structural solutions include engineered solutions such as redesigning buildings and designing physical barriers for disaster events in order to reduce damage. Non-structural solutions include social solutions such as early warning, evacuation planning, and emergency response preparedness [6].

Structural groups, which are often made up of engineers, insist that only structural solutions can prevent economic losses and contribute to the nation's development. On the other hand, non-structural groups often warn: Do not trust engineering solutions, because at some point they will not work. Early warnings, rapid evacuations and emergency responses are easy investments. The term “resilience” has recently been introduced into the dialogue on disaster management. The word implies that people must accept the damage of a disaster and have plans in place for recovery. As you know, alert, evacuation and emergency response can help save lives; however, it cannot protect physical properties and assets. For structural groups, non-structural solutions are not investments. Investments must contribute to development and therefore reduce future expenses. Structural solutions can protect people’s lives and property [6]. It is a false dilemma to choose between structural and non-structural measures to deal with flooding. We must opt for both measures. Non-structural measures should be taken in conjunction with structural measures as a precaution against the latter's failure to do so [6].

The United Nations IPCC has warned that sufficiently limiting man-made global warming will require rapid, far-reaching and unprecedented changes in all aspects of society in order to avoid dramatic global consequences, including rising sea levels, deaths of coral reefs and human casualties due to extreme heat. The special report - published by the United Nations Intergovernmental Panel on Climate Change - assessed what it will take to limit global temperature rise to no more than 2.7°F (1.5°C) above pre-industrial levels, according to the 2015 Paris Agreement. Scientists consider temperature to be a tipping point at which many severe effects of global warming will be realized [7].

The IPCC report called climate change an urgent and potentially irreversible threat to human societies and the planet, and warned that delaying action would make it impossible to limit warming to 2.7°F (1.5°C). While the pace of change that would be needed to limit warming to [2.7°F] can be traced back to the past, there is no historical precedent for the scale of transitions needed, particularly toward a socially and economically sustainable one, the report says. Resolving such issues of speed and scale would require people's support, public sector interventions, and private sector cooperation [7].

5. Cities planning required to face extreme weather events

To deal with extreme weather events, it is essential that governments prepare contingency plans to evacuate populations that may be affected as a result of floods, thus minimizing deaths and losses resulting from them. It is up to governments to inspect and monitor dams and adopt measures to prevent their failure. A large part of the resources should be allocated to prevention and not to cover losses as is currently the case because much less is spent on preventing floods than on rebuilding buildings and infrastructures. The municipal government plays a fundamental role in preventing flooding in cities. To this end, a municipal development master plan must be drawn up that includes, among other measures, the adoption of solutions to minimize or eliminate the risks faced by the population, the systematic identification of risk areas in order to establish population settlement rules. In addition, it must monitor risk areas, avoiding dangerous settlements, apply fines when residents do not comply with recommendations, prepare an evacuation plan with an alarm system and indicate areas that are safe for construction, based on zoning. Every resident must be informed of what and how to do to avoid being affected by floods [1].

Three bodies are essential in flood prevention actions in a municipality: 1) the municipal civil defense body, which is responsible for executing, coordinating and mobilizing all civil defense actions in the municipality, whose main task is to know and identify the risks of disasters in the municipality, preparing the population to face them by drawing up specific plans; 2) the body responsible for the meteorological service responsible for reporting the climate forecast for the city and/or region; and, 3) community civil defense centers, which are people who work voluntarily in civil defense activities, to collaborate with the civil defense body aiming at community participation, preparing it to respond promptly to disasters. It is up to the mayor to determine the creation of the civil defense body [1].

Sustainability is a term used to define human actions and activities that seek to meet the present needs of human beings without compromising the future of the next generations. In the case of floods, sustainability is achieved in their management when the environment affected by them is preserved for use by current and future generations with the adoption of prevention and precautionary measures against their occurrence. Sustainability is achieved in flood management with the development of prevention, precautionary and risk management plans, in addition to the intensification of inspection. To deal with flood risks, it is essential that prevention and precautionary measures are adopted to avoid catastrophic events. The Preliminary Environmental Impact Assessment of Floods is an important instrument for formulating civil defense plans, as it is used to assess, predict and prevent greater economic and social damage resulting from floods. It is worth noting that preventive or precautionary measures should underpin risk management policies and, above all, should be present in civil defense proposals and actions to combat floods [1].

Sea level rise is one of the best-known threats resulting from global warming and climate change. As humanity pollutes the atmosphere with greenhouse gases, the planet warms. As they do, ice sheets and glaciers melt and warming seawater expands, increasing the volume of water in the world's oceans. Globally, sea level rise could have a significant impact in the coming years. Potential impacts of sea level rise include flooding, erosion of coastal regions, and submergence of flat regions along the mainland coast and on islands.

According to Climate Central, a non-profit organization that analyzes and reports on climate science, made up of scientists and science journalists, which conducts scientific research on climate change and energy issues throughout the 21st century, considers that levels Global sea levels could increase by between around 61 cm and 2.13 m between 2030 and 2100 if nothing is done to prevent them. However, in some places on the planet the sea level could rise by up to 3.5 meters. In the extreme case, sea levels could rise by more than 7 meters if the ice caps, mountain ranges and Greenland melt [8]. The Greenland ice sheet alone contains enough water to raise sea levels by 7 meters, according to John Sutter's article “Climate: 9 questions on rising seas” [9]. Projecting where and when this increase could translate into increased partial flooding and permanent flooding is important for planning coastal regions and cities.

A new digital model, CoastalDEM, from Climate Central was used to identify flood areas on the planet. This is a high-precision digital elevation model for coastal areas that reduces average errors to nearly zero in NASA's widely used SRTM DEM and reveals flood threats three times greater. CoastalDEM shows that many of the world's coastal regions are at very low water levels and that rising sea levels could affect hundreds of millions of people in the coming decades more than previously thought. Based on sea level projections for 2050, the region of the planet currently home to 300 million people will fall below the elevation of an average annual coastal flood. By 2100, the region of the planet now home to 200 million people could be permanently below the high tide line [8].

What to do to face rising sea levels? The First Street Foundation, which published the article Solving for Sea Level Rise [8], offers answers with proposed solutions such as those described below:

Solution 1: Building Seawalls

One solution that cities employ to reduce tidal and storm flooding is the construction of seawalls. These barriers are generally built at a height of 1.52 meters to 1.83 meters above sea level. When seawalls or breakwaters age or are damaged by constant exposure to salt water or wave impact, they need to be reinforced or replaced. They also need to be reinforced, replaced or built higher as sea levels continue to rise.

Solution 2: Using beaches and dunes as barriers

Similar to seawalls, beaches and dunes can act as a natural wall and reduce the impact of ocean waves and storms. The longer the beach or the larger the dune, the more water can be prevented from reaching homes and roads. City rulers can add sand to widen beaches or to prevent them from eroding. Using this type of natural infrastructure can protect cities from flooding while maintaining beaches for the community to enjoy.

Solution 3: Raising the level of highways

Raising highways above sea level can help drain water and reduce tidal flooding. To ensure that higher roads do not channel floodwaters into homes and stores at lower elevations, city officials often pump stormwater to remove this excess water.

Solution 4: Stormwater pumping

With higher seas, water does not drain into the ocean as easily. Drainage systems are designed to channel excess rainwater from streets and drain it out to sea, but pressure from rising sea levels and high tides can push too much water into these pipes, causing water to leak into the streets. Pumps can speed up the process of removing water from streets, sucking up floodwater and releasing it back into the sea.

Solution 5: Updating Sewer Systems

Floods can disrupt sewage systems and, in particular, threaten septic tanks. As salt water is corrosive, it can damage tanks and cause sewage to be expelled, creating health risks for the population. City leaders can upgrade sewer systems so rainwater does not infiltrate pipes and upgrade septic tanks or replace them with sewer lines.

Solution 6: Creating natural infrastructure

Coastal communities can restore natural infrastructure, which can act as a buffer against storms and coastal flooding. Natural structures such as barrier islands, coral reefs, mangroves, sea grass beds and salt marshes can work alone or in conjunction with built infrastructure such as breakwaters to absorb storm surge. These projects are often cost-effective, can improve the natural environment for the community, and save important habitats.

Solution 7: Decreasing the land sinking

Cities can reduce land sinking by limiting groundwater pumping and starting pilot projects to reverse land sinking by filling empty space in places where groundwater has been pumped.

Solution 8: Planned relocation of populations

This solution is adopted in some coastal areas that are being lost to storms, rising sea levels, erosion and land sinking. Although communities are implementing many of the solutions available to help prevent land loss, relocation of populations in extreme cases should be considered. This may not be the best option for all coastal communities facing the imminent threat of sea level rise, but for some, it is the best solution to keep residents safe.

In addition to the local solutions described above, the measures recommended by the Paris Climate Agreement should be simultaneously adopted to reduce the global emission of greenhouse gases (carbon dioxide, nitrous oxide, among others) to avoid global warming of more than 2 degrees Celsius (°C) by the end of the 21st century [8].

Cities will be better able to face extreme climate events if they are transformed into smart and sustainable cities. Building smart and sustainable cities means providing rational management, improving the quality of life for the entire population, sustainable development of the city and democratization of government decisions with the participation of the entire population. Every city achieves the status of a smart city when its managers consider it as a system and use information technology in its planning and control process, counting on the effective support of its population. Every smart city requires the use of information technology with the use of various devices connected to the IoT (Internet of Things) network to manage the city's operations and services rationally and connect with its citizens [3].

The Internet of Things (IoT, in English) refers to a technological revolution that aims to connect everyday items used to the world wide web and is one of the main global trends its use in the administration of a city because it is applicable in solutions ranging from monitoring public lighting, pedestrians, cyclists, motor vehicles, public transport, education and health services, among others. The applications of the Internet of Things are almost endless. Furthermore, IoT will lead to a reduction in waste of public resources in cities. Driven by the rise of 5G Internet, IoT devices can bring benefits to people, companies and the public sector. However, it is worth highlighting that, to be considered an IoT solution, a city's administration system needs to have three characteristics: 1) receive digital data originating from sensors; 2) connect to an external network; and, 3) process information automatically, that is, without human intervention [3].

A new revolution in the media is about to occur with the use of 5G Internet across the world, representing to date the greatest advance in communications after a long historical process of technological evolution. 5G Internet will produce gigantic impacts on the economy and society. It is an absolutely innovative communications platform with features that allow machine-to-machine (M2M) communication with great efficiency, effectiveness, reliability and security. In this sense, it is developed for the internet of things (IoT), that is, for personal applications, but it also serves as a communications platform for the development of new and revolutionary applications for industry, cities, agriculture, transport and the services. The 5G Internet will be a major driver for the development of Industry 4.0 and the advent of smart cities because it tends to accelerate the development of technologies, such as the Internet of Things (IoT), artificial intelligence and machine learning, whose potential will not consist of only in improving connectivity for people, but allowing communication between objects, which can decisively transform urban services and spaces [3].

Information technology allows city managers to interact directly with their executing agencies and the population and monitor what is happening in the city and how the city is evolving in real time. Information technology should be used to improve the quality, performance and interactivity of urban services, reduce costs and resource consumption and increase contact between citizens and government. A smart city can be better prepared to respond to the challenges faced by its managers and its population. Every city will achieve the status of a smart city when the objectives of humanizing the city are achieved by improving the quality of life for the entire population, sustainable development of the city and democratization of government decisions with the participation of the entire population [3 ].

Improving the population's quality of life depends on the conditions of their existence in terms of employment, housing, basic sanitation, urban infrastructure, urban mobility and access to education, culture, health and leisure services. The sustainable development of a city will only be achieved when the degradation of natural resources is avoided and there are clear and comprehensive policies for sanitation, waste collection and treatment, water management, with collection, treatment, economy and reuse, transport systems that favor mass transport with quality and safety, actions that preserve and expand green areas, the use of clean and renewable energy and, above all, transparent public administration shared with organized civil society. In turn, the democratization of government decisions with the participation of the entire population will only exist when they become involved not only in providing data, but also decide on the city's direction [3].

Among the world's smart cities, the following stand out: 1) Amsterdam, which has, since 2009, an interconnected platform through wireless devices to improve the city's decision-making abilities in real time, reduce traffic, save energy and improve public safety; 2) Copenhagen, which, in 2014, won the prestigious World Smart Cities Award for its smart city development strategy aimed at improving air quality, liveability and traffic flow; 3) Dubai, which has a project to become a smart city by 2030, with transport initiatives that include driverless vehicles, digitalization of government, business and customer transactions; and, 4) Stockholm, which aims to create a green IT structure to reduce environmental impact, increase the energy efficiency of buildings and traffic monitoring, among other objectives [3].

It is an imperative need to make cities smart because the city has become the main habitat of humanity. For the first time in human history, more than half of the population lives in cities. This number, 3.3 billion people, is expected to surpass the 5 billion mark by 2030. At the beginning of the 20th century, the urban population did not exceed 220 million people. Access to jobs, services, public facilities and greater economic and social well-being is its greatest attraction for all who seek it [3]. A large part of global environmental problems originate in cities, which makes it difficult to achieve sustainability at a global level without making them smart [3].

Significant impacts on the environment occur due to the modes of production and consumption in urbanized spaces. Pollution, traffic jams, violence, unemployment, etc., are common in cities. Water pollution is mainly caused by the release of untreated industrial and domestic effluents. Air pollution is a major problem detected in cities that results from the release of toxic gases into the atmosphere. The intense flow of cars and industries is mainly responsible for this type of pollution. Other environmental problems resulting from urbanization are soil sealing, visual pollution, noise pollution, climate change, acid rain, lack of environmental sanitation, lack of adequate disposal and treatment of solid waste, greenhouse effect, among others. The lack of effective urban planning compromises the quality of life of the urban population. The disorderly growth of cities generates the occupation of places unsuitable for housing low-income populations, such as those with high slopes, valley bottoms, among others [3].

The accelerated urbanization and growth of cities, especially since the mid-20th century, has promoted physiognomic changes on the planet, more than any other human activity. It is in cities that the social, economic and environmental dimensions of sustainable development converge most intensely, making it necessary to structure smart cities that are designed, managed and planned in accordance with the sustainable development model that aims to meet current needs of the Earth's population without compromising its natural resources, bequeathing them to future generations. This means that the smart and sustainable development model in cities must be adopted with the aim of making economic and social factors compatible with the environment [3].

In the contemporary era, when the problems of global warming can lead to catastrophic climate change on a planetary scale, every city needs to have a climate change adaptation plan, especially those subject to extreme events. Coastal cities, for example, must plan against the predictable rise in ocean levels and worry about landslides on slopes, floods, etc., resulting from inclement rain. In short, they must have flexibility and adaptability to new climatic requirements. It is necessary to redesign the urban growth of cities to integrate it with the natural environment and recover its beaches and rivers that are now compromised by the release of sewage, so that cities do not receive a hostile response from the natural environment [3].

Significant impacts on the environment occur due to the modes of production and consumption in urbanized spaces. Pollution, traffic jams, violence, unemployment, etc., are common in cities. Water pollution is mainly caused by the release of untreated industrial and domestic effluents. Air pollution is a major problem detected in cities that results from the release of toxic gases into the atmosphere. The intense flow of cars and industries is mainly responsible for this type of pollution. Other environmental problems resulting from urbanization are soil sealing, visual pollution, noise pollution, climate change, acid rain, lack of environmental sanitation, lack of adequate disposal and treatment of solid waste, greenhouse effect, among others. The lack of effective urban planning compromises the quality of life of the urban population. The disorderly growth of cities generates the occupation of places unsuitable for housing low-income populations, such as those with high slopes, valley bottoms, among others [3].

The accelerated urbanization and growth of cities, especially since the mid-20th century, has promoted physiognomic changes on the planet, more than any other human activity. It is in cities that the social, economic and environmental dimensions of sustainable development converge most intensely, making it necessary to structure smart cities that are designed, managed and planned in accordance with the sustainable development model that aims to meet current needs of the Earth's population without compromising its natural resources, bequeathing them to future generations. This means that the smart and sustainable development model in cities must be adopted with the aim of making economic and social factors compatible with the environment [3].

After all, what characterizes a smart and sustainable city? It is for the city to be managed rationally with the support of the population with the use of information technology, which ensures the population's right to urban land, housing, environmental sanitation, urban infrastructure, transport and public services, work and to leisure, for current and future generations and which ensures the population's right to decide on the destiny of their city. Transforming a city into a smart city means using information technology to facilitate city management with the collaboration of the population and counting on their participation in decision-making. The future of cities and their populations therefore depends on what is done to adopt a new management model with the use of information technology, promote improved quality of life for the entire population, promote the sustainable development of city and promote the democratization of government decisions with the participation of the entire population [3].

The facts of life are increasingly showing the need for the paradigm that has guided the development of human society since the 1st Industrial Revolution to be profoundly modified. This is why the current model of society must be replaced by the sustainable development model, among other measures. Some measures need to be implemented to stop the current rate of global warming [4]:

? Reduce carbon emissions by 45%

By 2030, global carbon dioxide emissions are expected to be 45% lower than in 2010, according to the report. Carbon dioxide emissions are expected to be zero by around 2075, meaning the amount of carbon dioxide entering the atmosphere equals the amount to be removed. By 2050, emissions of other greenhouse gases, including methane and carbon black, must be reduced by 35% from the 2010 rate. Emissions would need to decline rapidly in all major sectors of society, including buildings, industry, transport, energy and agriculture, forestry and other land uses.

? Remove carbon dioxide from the air

In addition to reducing carbon dioxide emissions, reported carbon dioxide removal measures include planting new trees and carbon capture and storage, the process by which carbon dioxide is captured and prevented from entering the atmosphere. Most current and potential carbon dioxide removal measures could have significant impacts on land, energy, water or nutrients if implemented on a large scale.

? Use 85% renewable energy and stop using coal entirely

The report recommended far-reaching changes to land use, urban planning, infrastructure systems and energy use – changes that will be “unprecedented in terms of scale”. Climate scientists have said that renewable energy sources will have to account for 70% to 85% of electricity production by 2050. Coal use is expected to decline sharply and is expected to account for almost 0% of global electricity, and gas just 8% . While recognizing the challenges and differences between national options and circumstances, the political, economic, social and technical viability of solar energy, wind energy and electricity storage technologies have improved substantially in recent years. These improvements signal a possible system transition in electricity generation.

? Plant new forests equal to the size of Canada

Scientists recommend that up to 3 million square miles of grassland and up to 1.9 million square miles of non-grazing farmland be converted into up to 2.7 million square miles for energy crops, which can be used to produce biofuels. This would equate to an amount of land slightly smaller than the size of Australia. The report also recommends adding 3.9 million square miles of forests by 2050, up from 2010 — which is about the size of Canada.

REFERENCES

1.????????????ALCOFORADO, Fernando. How to cope with extreme weather events in Brazilian cities. Available on the website <https://www.academia.edu/113388717/HOW_TO_COPE_WITH_EXTREME_WEATHER_EVENTS_IN_BRAZILIAN_CITIES >.

2.??????????????ALCOFORADO, Fernando. City floods and global climate change. Available on the website <https://www.dhirubhai.net/pulse/city-floods-global-climate-change-fernando-alcoforado/ >.

3.????????????? ALCOFORADO, Fernando. How to build smart and sustainable cities. ??Available on the website <https://www.academia.edu/61050601/HOW_TO_BUILD_SMART_AND_SUSTAINABLE_CITIES >.

4.????????????? ALCOFORADO, Fernando. Catastrophic Climate Change Requires New Society Model. Available on the website <https://www.heraldopenaccess.us/openaccess/catastrophic-climate-change-requires-new-society-model >.

5.????????????? ALCOFORADO, Fernando. Sustainability in flood management. Available on the website <https://www.dhirubhai.net/pulse/sustainability-flood-management-fernando-a-g-alcoforado/ >. ?It′s a chapter in the book Flood Handbook (CRC Press, Boca Raton, Florida United States, 2022).

6.????????????? ALCOFORADO, Fernando. How to prepare cities against extreme climate events. Available on the website <https://www.dhirubhai.net/pulse/how-prepare-cities-against-extreme-climate-events-fernando-alcoforado/ >.

7.????????????? ALCOFORADO, Fernando. Strategies to deal with global climate change. Available on the website <https://www.dhirubhai.net/pulse/strategies-deal-global-climate-change-fernando-a-g-alcoforado/

8.????????????? FIRST STREET FOUNDATION.? Solving for Sea Level Rise. Disponível no website <https://medium.com/firststreet/solving-for-sea-level-rise-b95600751525 >.

9.????????????? SUTTER, John. Climate: 9 questions on rising seas, Disponível no website <https://edition.cnn.com/2015/05/05/opinions/sutter-sea-level-climate/index.html >.

* Fernando Alcoforado, awarded the medal of Engineering Merit of the CONFEA / CREA System, member of the Bahia Academy of Education, of the SBPC- Brazilian Society for the Progress of Science and of IPB- Polytechnic Institute of Bahia, engineer from the UFBA Polytechnic School and doctor in Territorial Planning and Regional Development from the University of Barcelona, college professor (Engineering, Economy and Administration) and consultant in the areas of strategic planning, business planning, regional planning, urban planning and energy systems, was Advisor to the Vice President of Engineering and Technology at LIGHT S.A. Electric power distribution company from Rio de Janeiro, Strategic Planning Coordinator of CEPED- Bahia Research and Development Center, Undersecretary of Energy of the State of Bahia, Secretary of Planning of Salvador, is the author of the books Globaliza??o (Editora Nobel, S?o Paulo, 1997), De Collor a FHC- O Brasil e a Nova (Des)ordem Mundial (Editora Nobel, S?o Paulo, 1998), Um Projeto para o Brasil (Editora Nobel, S?o Paulo, 2000), Os condicionantes do desenvolvimento do Estado da Bahia (Tese de doutorado. Universidade de Barcelona,https://www.tesisenred.net/handle/10803/1944 , 2003), Globaliza??o e Desenvolvimento (Editora Nobel, S?o Paulo, 2006), Bahia- Desenvolvimento do Século XVI ao Século XX e Objetivos Estratégicos na Era Contemporanea (EGBA, Salvador, 2008), The Necessary Conditions of the Economic and Social Development- The Case of the State of Bahia (VDM Verlag Dr. Müller Aktiengesellschaft & Co. KG, Saarbrücken, Germany, 2010), Aquecimento Global e Catástrofe Planetária (Viena- Editora e Gráfica, Santa Cruz do Rio Pardo, S?o Paulo, 2010), Amaz?nia Sustentável- Para o progresso do Brasil e combate ao aquecimento global (Viena- Editora e Gráfica, Santa Cruz do Rio Pardo, S?o Paulo, 2011), Os Fatores Condicionantes do Desenvolvimento Econ?mico e Social (Editora CRV, Curitiba, 2012), Energia no Mundo e no Brasil- Energia e Mudan?a Climática Catastrófica no Século XXI (Editora CRV, Curitiba, 2015), As Grandes Revolu??es Científicas, Econ?micas e Sociais que Mudaram o Mundo (Editora CRV, Curitiba, 2016), A Inven??o de um novo Brasil (Editora CRV, Curitiba, 2017),? Esquerda x Direita e a sua convergência (Associa??o Baiana de Imprensa, Salvador, 2018), Como inventar o futuro para mudar o mundo (Editora CRV, Curitiba, 2019), A humanidade amea?ada e as estratégias para sua sobrevivência (Editora Dialética, S?o Paulo, 2021), A escalada da ciência e da tecnologia e sua contribui??o ao progresso e à sobrevivência da humanidade (Editora CRV, Curitiba, 2022), a chapter in the book Flood Handbook (CRC Press,? Boca Raton, Florida United States, 2022), How to protect human beings from threats to their existence and avoid the extinction of humanity (Generis Publishing, Europe, Republic of Moldova, Chi?in?u, 2023) and A revolu??o da educa??o necessária ao Brasil na era contemporanea (Editora CRV, Curitiba, 2023).?

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