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Mitigating and adaptive actions are urgently needed to combat extreme climate events

The global average temperature has increased by about 1.1°C since the pre-industrial period (1850-1900). Human activity is responsible for warming the atmosphere, oceans and land. Without significant reductions in greenhouse gas emissions, global warming could exceed 1.5°C and 2°C this century.

Por: Gabriela Andrietta

In 2021, the IPCC (Intergovernmental Panel on Climate Change) released the report "Climate Change 2021: The Physical Science Basis", warning about the increase in the frequency and intensity of extreme weather events due to climate change.

These events include heat waves, intense rainfall, droughts, floods, cyclones and compound events, such as extreme heat and simultaneous drought. Human-caused greenhouse gas emissions have increased the frequency and intensity of extreme weather events, especially related to temperature extremes. Small increases in global temperature can cause large changes in regional and global climate extremes, making these events even more frequent and intense.

Since 1950, the frequency and intensity of heat extremes have increased, while cold extremes have declined globally. Human influence, mainly through greenhouse gases, is the main cause of these changes. Heavy precipitation has increased in most regions of the Earth, with greenhouse gas emissions being the main cause. Droughts have also increased in some regions due to greater evapotranspiration caused by climate change. With continued global warming, the frequency and intensity of extreme events, such as cyclones and severe droughts, may increase. The likelihood of compound climate events, such as simultaneous heat waves and droughts, continues to grow.

Professor Newton La Scala Jr., from Unesp in Jaboticabal, researches climate change, soil science and sustainable agricultural practices. His studies on the impact of agricultural activities on greenhouse gas emissions point to ways of mitigating these effects. The professor highlighted that the IPCC plays a crucial role in understanding global climate change. 

Global warming and increase in CO2 in the atmosphere

The IPCC compiles data and presents scientific research reports. Recently, a synthesis report was published, released in 2023, which includes paleoclimatic data obtained from ice cores, such as those from the Vostok site in Antarctica.

As explained by Professor Newton La Scala Jr, these data show that the ice sheet in Antarctica, formed over the last 500 to 600 thousand years, contains historical records of the concentration of CO2 in the atmosphere. Analyzes reveal that every 100,000 years there is a peak in CO2 concentration, with the most recent levels reaching approximately 400 ppm due to human activities.

According to Professor Newton, "Antarctica has at its center about three kilometers of ice layer, and this ice layer was formed by deposition in the last 500, 600 thousand years. If you drill a hole and remove the ice that exists from the surface to a certain depth, inside this ice you have air bubbles from the time when this ice was formed. These measurements can be made directly in these bubbles inside the ice. in the atmosphere, in ppm. Approximately every 100,000 years, there is a peak, and here is the closest to the present. Human activities, especially the use of fossil fuels and deforestation, have recently driven this concentration of CO2 into the atmosphere. of 400 ppm. Nowadays, the concentration of CO2 in the atmosphere is more than 400 ppm, closer to 410 ppm, and this has occurred mainly in the last 200 years.

Based on isotopic analyses, it is possible to make a regression of the temperature at which this species lived. Every 100,000 years, there is a peak in the planet's average temperature. Zero would be close to the current one. The planet has already had a temperature in the last 300 thousand years, approximately 2 degrees above what it is today. Currently, the planet's average temperature is around 15, 16 degrees, but it has had temperatures 8 degrees below what it is today. These fluctuations in the concentration of CO2 in the atmosphere and in the paleoclimatic data, CO2, methane, nitrous oxide, fluctuate greatly in accordance with the fluctuations in the planet's average temperature. Climate models are validated with this data, so you have climate models from different agencies that are validated with this data and from several other places that were extracted. This ice core data is taken from Antarctica and also from the Arctic, and so the planet's average temperature has its fluctuations.

Over the past 200 years, the concentration of CO2 in the atmosphere has increased significantly, exceeding 400 ppm. This increase, mainly attributed to the burning of fossil fuels and deforestation, coincides with a global average temperature increase of about 1.2 degrees Celsius since the pre-industrial era. Temperature extremes, both maximum and minimum, have increased in recent decades.

Extreme weather events

With extreme events, increases in temperature and extreme precipitation have been observed, as well as consecutive days of drought. The highest temperature of the year and the lowest temperature of the year show these increasing trends. These indicators reflect global warming and its direct consequences. The 2023 synthesis report also highlights an increase in extreme precipitation, including the southern region of Brazil.

Professor Newton highlighted that "about extremes, firstly, it is possible to score temperature extremes. Every 10 years, in a given location, the highest temperature of the year is measured and recorded. From 1960 to 2018, these data are observed at meteorological stations. In a very extreme case, of 1 degree every 10 years, in 70 years, we have areas on the planet where the hottest temperature observed in the year has already increased by 7 degrees, for example. coldest of the year, which is usually at night. With each decade, this is also increasing. And the number of days whose temperature exceeds the 90% most recorded is also increasing. Regarding extreme precipitation, in the summary report published in 2023 , he reports the increase observed in the world. In southern Brazil, there is an increase in heavier precipitation. In relation to consecutive days of drought, these are the trends observed from 1960 to 2018, per decade. more days every ten years of consecutive droughts. And this is spatialized across continents."

Impacts, Mitigation and Adaptation

The impacts of these extreme events and climate change on agriculture and food production are significant. On some continents, these impacts are both negative and positive, depending on local conditions.

The report emphasizes the importance of mitigation, which involves reducing greenhouse gas emissions and capturing atmospheric CO2. Sectors such as solar energy, wind energy, agriculture and ecosystem restoration are crucial. Reducing deforestation and implementing agroforestry systems are highlighted as effective strategies to capture CO2 and improve the resilience of agricultural systems. Professor Newton explained that "there are multiple opportunities and needs for mitigation, whether this mitigation is understood as reducing emissions or capturing CO2, carbon sequestration. Global emissions closed in 2023 at close to 60 billion tons of CO2 equivalent. Sectors such as energy supply, land use, water and food production have significant mitigating opportunities. The main sectors highlighted are: solar energy, and wind energy in energy supply. Deforestation could save around 4 gigatons of CO2 per year. Carbon sequestration in agriculture and the restoration of ecosystems, or in degraded agricultural systems, are also crucial. Adding these potentials, we are talking about 15 gigatons of CO2 equivalent, which are opportunities. real efforts to reduce the concentration of CO2 in the atmosphere."

Implementing sustainable policies and practices can help mitigate greenhouse gas emissions and increase the resilience of agricultural and natural systems to climate change. Adaptation is the practice of adjusting systems and communities to reduce the negative impacts of climate change. Adaptive capacity is greater in communities with access to resources and knowledge about resilient practices. Strengthening infrastructure, food security policies, and sustainable resource management are essential for adapting to climate change. As  Professor Newton explains, “With regards to adaptation, reducing climate risk through adaptations is a reality, and adaptive capacity depends on how countries can manage the resources and knowledge to implement resilient practices.

Agroforestry, for example, has had positive impacts on reducing carbon emissions and capturing. Agroforestry systems, which combine agriculture, livestock and forestry, can be viable solutions to mitigate climate change, increasing CO2 capture in biomass and soil. These systems not only help with mitigation but also with adaptation, providing a more stable environment for crop and livestock production.

As highlighted by Professor Newton, "Agroforests are complex agricultural systems that can involve livestock and forest, agriculture and forest, or a combination of agriculture, livestock and forest. In addition to helping with mitigation, these systems capture CO2 as that the forest grows, depending on the spacing and density of the forest. CO2 is incorporated into the biomass of plants, which are highly capable of doing this, and a desirable accumulation of carbon in the soil can also occur.

From a gas balance point of view, it is perfectly possible to achieve a balance close to zero by integrating agricultural production with forest growth. I published works on this together with former students, and in 2015 and 2016 we discussed the balance of greenhouse gases in meat production systems, degraded pastures, well-managed pastures and crop-livestock-forest integration."

However, in addition to the issue of mitigation, there is also, especially when it comes to animals, the issue of adaptation. As explained by Professor Newton, "often, a system like this is proving to be more suitable or, sometimes, even more productive, because the animals have an environment with lower temperatures and higher air humidity. Agriculture is already implementing this very well, as the main interest is efficient production, without losses, and increased productivity. To improve productivity, many adaptations are already being made in agriculture and, especially, in livestock farming. and coffee with forests, there is a small drop in productivity, the benefit of the balance of greenhouse gases in meat production systems, degraded pasture, well-managed pasture and crop-livestock-forest integration is significant."

Future Perspectives and Public Policies

Future projections unfortunately indicate the possibility of worsening. However, with appropriate reversal actions, we can achieve a more favorable outlook. These projections depend largely on the measures we take in the future and how these actions affected the concentration of greenhouse gases in the atmosphere.

Professor Newton reinforced that “The increase in maximum temperature during the day and the increase in temperature at night have a series of influences and this begins to be harmful for agricultural productivity itself, for animals and livestock as well. In the case of Brazil, the largest greenhouse gas emissions result from deforestation, which needs to be controlled until we reach zero deforestation. Our country has large areas previously used as pastures, now degraded, that could be better used for agriculture, integrating them with forests and creating a healthier environment for agricultural production and other aspects.

Agroforests, in addition to favoring the balance of greenhouse gases through the capture of CO2 and incorporation of carbon into biomass and soil, bring other benefits, such as increasing biodiversity, improving the hydrological cycle, reducing maximum temperatures in the region and increasing relative air humidity.

These advantages occur mainly due to adaptation. If there were a mechanism to encourage and remunerate farmers to make such transitions, such as a carbon credit system or carbon market, this ecological transition in agricultural systems could be accelerated. This would be desirable not only from the point of view of the greenhouse gas balance, but also for other benefits related to agroforestry and its multiple environmental advantages.

These mechanisms that finance transitions, such as energy efficiency or a possible ecological transition, could count on international financing. However, public policy is fundamental in this process. Brazil is currently approving the Brazilian Emissions Trading System in the Senate, which can encourage these transitions aimed at removing CO2 from the atmosphere and its incorporation into soil and biomass, through reforestation. This would benefit farmers by accelerating these transitions.

In Brazil, depending on the biome, such as the Atlantic Forest and Cerrado, farmers must conserve 20% of their land as a legal reserve, a native forest provided for by law. With a mechanism that rewards farmers for regenerating their areas and expanding protection and reforestation zones, they could receive credits for this. This would not only combat climate change, but also improve biodiversity, the hydrological cycle, relative air humidity and thermal comfort in the regions. Although it is still a challenge, we are close to creating a mechanism in this direction, which I see as very possible.”

The IPCC highlights that these activities have the greatest potential for carbon capture worldwide, especially in Brazil. Carbon sequestration in soil and biomass in reforestation areas has enormous potential, considering the extensive areas in Brazil that could be reforested, contributing significantly to the balance of greenhouse gases. It is feasible for Brazil to reach a balance close to zero, or even negative, before 2030, if it continues in this direction. These are feasible estimates, depending on the policies that will be implemented.

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