Extreme climate events, such as heavy and destructive rains, are no longer exceptions that are far from time but an inevitable threat, with many new examples in Chile and around the world. In a column for CIPER, a geographer and university professor on climate change details the scope of this risk and also the “steps of change” that seek a solution, as in the case of our country in the park of Kaukari (Copiapó) and the wetlands of Baquedano. (Llanquihue).
The warm frontal system that a few days ago was felt in most of central and southern Chile left unexpected damage. Thousands of victims, houses,, and infrastructure were destroyed, and even deaths were the result of these heavy rains that occurred in the context of a severe drought. Among the many challenges of climate change, extreme weather events will become more frequent, and we must ask ourselves how prepared we are to face them.
Regarding the ability to project the future climate, there are various useful sources of information to anticipate the behavior of relevant climate variables, such as precipitation and temperature (IPCC, CR2, NASA, Copernicus). For example, the Climate Risk Atlas, a platform of the Ministry of the Environment prepared by the Chilean scientific community, makes available relevant climate projections such as heavy rainfall. The Atlas shows that the projection of accumulated snow in mountainous areas in the regions most affected by the frontal system will decrease by approximately 50 to 70%. However, the projection for accumulated precipitation (rain and snow) for these same regions will not decrease significantly (about 16%). In other words, it rains where it snows.
Another piece of information that bolsters the Atlas projections is the rise in elevation of the 0°C isotherm (limit between solid and liquid precipitation), a concept that has had extensive media exposure and needs to be explained. of alluvial phenomena in Chile. According to the Climate Report of the Chilean Meteorological Directorate, the 0°C isotherm has increased by 70 m/decade in the central zone. The confirmation of the increased possibility of liquid rain in high mountain areas (areas with high slopes and a lack of consolidated soil) is the confirmation of the increased risk of flooding in the future. The presence of consolidated soil helps to retain the sediments during the rains, but the lack of soil, as happened in the Atacama Desert or in the mountainous areas, has the opposite effect, allowing the rain to carry large quantities. in the sediment of his hay. . As if this were not enough, the reduction of accumulated snow (or the increase of the 0°C isotherm) has effects on drought since it is a natural reservoir of water for dry periods (functioning higher).
According to the Intergovernmental Panel on Climate Change (IPCC), extreme weather events represent one of the main threats to climate change. Heavy rains are becoming more frequent in different regions of the planet, creating effects of unimaginable proportions. An example is Pakistan, a country that last year suffered an unusually heavy monsoon rain, which caused the displacement of millions of people (eight million are still in the situation), the destruction of critical infrastructure (houses, bridges, dams), and the loss of a large part of that year’s crops. The consequences of the flood caused the country to collapse socially and economically. Another recent example is the devastating summer floods that occurred in Europe (especially in Belgium and Germany) in 2021, where 200 people lost their lives and the damage to houses and infrastructure amounted to billions.
These examples are just a sample of the level of destruction these events can reach, but there are many others, such as in the case of the US, with the recent floods in Florida, or the floods in Australia. Climate change has major impacts around the world, and it is urgent to take steps to adapt to its consequences.
As for the solutions, it is difficult to find a measure that completely solves this problem. Of course, it makes sense to implement strategies to prevent people from settling in high-risk areas, such as river banks. However, the scale and magnitude of these events make relocating people or infrastructure an extremely expensive and complex undertaking. In a future where it is expected to face more similar events, the measures implemented during this event (early warning systems and evacuation plans for critical areas) are very necessary. For its part, the scientific community is asking for the strengthening of monitoring technology that allows the population to be more accurately alerted about the development of typhoons like the one we recently experienced.
From the point of view of planning and configuring our cities, infrastructure, and public spaces, it is important to include the concept of nature-based solutions (NBS). China has taken a bold approach in this regard through a planning policy known as “sponge cities.” Floods, which are becoming more frequent in that country, have become a very serious problem, causing damage to many cities and stopping production (in a country that cannot stop). The goal is for 80% of cities (located in floodplains) to absorb and recycle 70% of rainwater by the year 2030. Some of the measures being considered are floodplain parks along the rivers, creating artificial wetlands, planting trees on the sides of roads, and using permeable materials for the construction of streets and squares. These types of solutions are called “change measures” (or measures that seek a paradigm shift in terms of solving the challenges of climate change). The IPCC, in its most recent report (AR6), encourages the implementation of these types of measures.
In Chile, we have successful examples of transformative measures. Kaukari Park in the city of Copiapó is designed to contain the flooding that occurs due to occasional rains. At the same time, the project considers the renaturalization of the river bed (SbN) and the construction of quality public spaces, including the possibility of walking along the river. The park not only increases the resilience of the city to floods but also transforms into a public space that improves the quality of life of the inhabitants of Copiapó. Another small example is the Baquedano wetland, located in a residential neighborhood in the city of Llanquihue. Thanks to its conservation, the swamp maintains its ecosystem function and can take excess water from heavy rains, preventing flooding of the surrounding houses (it acts like a sponge).
Change measures (including NbS) should be widely discussed and prioritized by our authorities in the context of climate change and the high demand for more ecological and fair cities.