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Global warming increases floods and droughts

Natural disasters related to water are the ones that have caused the most human and economic losses in the last 50 years in different parts of the world. In the last decade, hazardous natural phenomena related to water increased 9% compared to the previous decade. The sum of events is increasingly powerful. According to an analysis by the World Meteorological Organization (WMO), whose Atlas on mortality and economic losses due to extreme meteorological, climatic and hydrological phenomena (1970-2019) will be presented in September, droughts, storms, and floods top the list of the worst natural disasters with about a million and a half deaths.

The explanation for its violent and gradual impact is summed up each year in one sentence: effects of global warming; however, the phenomenon seems not to be taken very seriously. Neither solution is paid with the required speed, despite constant reminders from nature, such as the floods that recently killed hundreds in Germany, Belgium, and the Netherlands. According to "Atlas", the storms and floods inflicted the largest economic losses in Europe in the last 50 years: 377.5 billion dollars.

German climatologist Friederike Elly Luise Otto, Associate Director of the Institute for Environmental Change at the University of Oxford focuses her research on the relationship between extreme weather conditions and global warming. Greater atmospheric warming retains more moisture, leading to more vigorous rains. But relating this equation to global warming requires accurate monitoring of a large amount of data generated over many years.

The recently published document Extreme Weather Events and Impacts Inventories: Implications for Loss and Damage and Adaptation to Climate Extremes, recently published by scholars led by Otto, concludes that extreme weather events of the recent past provide key data source. but underused to understand current and future climate risks. The information on extreme events (EEA) allows to quantify the influence of anthropogenic climate change (ACC), and helps to create better strategies against it.

In the research, examples are used where information is systematically recorded to relate events of high-risk impact and the consequences of human losses. These data helped determine, for example, that in the United Kingdom since 2000, at least 1,500 deaths are directly attributable to human-induced climate change; or that in Puerto Rico, the increase in the intensity of Hurricane María alone caused the death of 3,670 people.

The planet is big and the count is long, but the data inventories of past events are not anecdotes, they form a basis for an in-depth analysis that involves identifying the most damaging hazards and specific vulnerabilities in certain places and populations, as well as the characteristics particular and global exposure of these phenomena over time. The heatwaves in the United States and Canada above 49.6 °, prior to the European flood, show that the climate is crossing a more dangerous threshold where new forecasting parameters need to be created.

To construct a risk assessment for heat-related mortality in a given population, they focus on a vulnerable group, such as urban elderly populations, and project changes in hazard and exposure within the same framework. Without preparation, the risk for this group is likely to increase by 50% by 2028 and 150% by 2043. These assessments also allow exploring the probability of unprecedented events, called black swans.

Historical data inventories not only aid disaster preparedness and adaptation at the local and national level but provide new evidence for global inventories on the counting of losses and damages, as required by the Paris Climate Agreement.

The 26th session of the Conference of the Parties (COP 26) to the United Nations Framework Convention on Climate Change (UNFCCC) will take place in November in Glasgow, Scotland. It seeks to reach an agreement on the need for policies in various areas to deal with the climate emergency. One of the most worrying points is the food shortage. Three years ago it was already warned that if the global temperature rises more than 1.5 degrees Celsius, floods and crop losses would open the way to chaos.

Early warning systems

According to the World Meteorological Organization (WMO), as climate change and demographic transformation increase the number of people exposed to floods, heatwaves, and other hazards, it is essential to have better warning systems and better coordination of emergency activities. disaster management.

The recent rains in Europe and Asia revealed that improvement in these types of systems is not just a matter for developing countries. The data collected with the geospatial tools and the alerts issued digitally were not enough, so the experts coincide in rethinking local strategies where populations with specific needs and tools at their disposal are contemplated.

The WMO emphasizes the usefulness of so-called multi-hazard alerts, as alert channels are known for various types of risk, from storms to extreme temperatures, evaluating combined risks of natural phenomena that could cause floods, landslides, fires, and other damages in potentially affected localities. WMO Secretary-General Petteri Taalas has said that water is the main vehicle with which we feel the effects of climate change. No country - developed or developing - is immune to this phenomenon. Climate change is here. We must urgently invest more in adapting and one way to do that is by strengthening early warning systems.

Only 40% of countries currently have effective warning systems, but the benefits of investments in early warning systems are seen to multiply in many areas. Investing $ 1.8 billion in improvements to hydrometeorological services between 2021 and 2030 worldwide could generate $ 7 billion in total net benefits.

One of the pioneer cities in multi-risk alert systems in Shanghai, a city that concentrates around 24 million inhabitants and maintains an effective system that issues alerts for tropical cyclones, storm surges, and extreme temperatures, as well as floods and even diseases. and potential physical damages derived from these phenomena.

Early warning systems have been improved thanks to progress in weather and climate prediction. WMO data indicate that predictions have improved by about one day every seven to eight years, so current five-day predictions are just as accurate as two-day predictions offered some 25 years ago, but phenomena have increased. to such a degree that its impact sometimes exceeds the most functional alerts.

Urban planning issues prevail in many parts of the world that continue to repeatedly complicate emergency management, as is the case in Tabasco, where settlements in low-lying areas distorted the original circulation of water, and poor design and management of works to water control still causes periodic flooding. Added to old vices around the world is the evident impact of climate change.

Mexico continues to bet on oil, while other countries have set ambitious goals to try to lower their emissions. The European Commission plans to stop selling gasoline and diesel cars by 2035. The disasters fueled by global warming have left a profound mark not only in the developing world but also in first-world nations that discover vulnerabilities to the account. of a century of polluting resources that today demand immediate payment.

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