If global commitments to CO2 reduction are not achieved by 2030, in the case of Mexico the outlook will be dramatic because the temperature could rise to seven degrees by the end of the century, warned Ruth Cerezo-Mota, of the UNAM Engineering Institute, Sisal academic unit.

Meanwhile, the director of the National Institute of Ecology and Climate Change (INECC), María Amparo Martínez Arroyo, added: it is estimated that at least four centimeters of coastline will be lost every year, a situation that increases the problems for cities located along the 11,500 kilometers of coastline, such as flooding, salinization of water in wells, etcetera.

Currently, the expected annual damage (DAE) in Mexico due to river floods is seven billion dollars and for coastal floods, 130 million dollars. It is believed that Tamaulipas, Veracruz, and San Luis Potosí will have the highest levels of risk. In addition, it is expected that by 2080, the DAE for coastal flooding due to economic development and climate change will be 116 billion dollars per year.

Both specialists participated in the Permanent Seminar on Sustainable Cities and Climate Change of UNAM's University Program for City Studies (PUEC). They emphasized that the effects of climate change will last for decades and cannot be stopped, so it is necessary to adapt dynamically, in addition to identifying vulnerabilities for each specific locality.

Cerezo-Mota, the only Mexican who participated in the preparation of the latest report of the Intergovernmental Panel on Climate Change (IPCC), exemplified that if in Merida during March or April it reaches 40 degrees Celsius, the lack of international action would mean reaching 47 degrees Celsius in the area.

"Mexico is a coastal country and it is a fact that sea levels will continue to rise. Although it is inevitable, the difference is how much. If we do something we would have an increase in the sea level of up to 50 centimeters by the end of this century, if we go to the scenario of the highest amount of emissions, it would be up to one meter 50 on average by 2100", she pointed out.

The researcher from the Laboratory of Engineering and Coastal Processes explained that for some time now experts have been trying to find out what will happen in three scenarios: in the first one, emissions are reduced and the temperature rises 1.5 degrees; the next one, where actions are implemented, but the goal is not reached; and finally, the one where nothing is done.

"Unfortunately, in any of the scenarios for 2030 we will be reaching 1.5 degrees, the difference is if we begin to gradually lower the temperature, but the medium and high-risk scenario would imply increases of 4 degrees of global average temperature, which for Mexico implies an increase of up to 7 degrees above the average and that implies putting people's health at risk, loss of crops, loss of livestock, etc.," said the climate change expert.

Hence, without concrete actions, intense droughts will be observed, with a significant rainfall deficit of up to 30 percent less liquid. In addition, extreme wet events such as torrential rains are expected to occur, she said. Cerezo-Mota added that Mexico has signed multiple climate agreements and at this time it should move towards the use of renewable energies; that is to say, promote solar, wind, or new energy sources.

The sector that pollutes the most is the burning of fuel for energy generation, followed by private and public transportation, so it is necessary to promote the electric sector or transition to energies that do not depend on fossil fuels. At a societal level, there are multiple actions such as avoiding food waste, which generates eight percent of pollutant emissions, reducing meat consumption, recycling garbage, separating it correctly, using energy-saving light bulbs and cloth bags.

Greater attention to urban areas

In turn, María Amparo Martínez Arroyo said: "We cannot have something different with the same thing. If we do not create another type of mobility, not only talk about other transportation. Of course, an electromobility is an important option, but also multimodal transportation (by bicycle to a certain extent, trains or buses) in a collective way, this is important and has to do with the structure of the city and the organization of activities".

During her talk "Climate policy in Mexico: Advances and challenges in cities", the UNAM researcher also pointed out that cities occupy less than two percent of the planet's surface and are home to more than 50 percent of the world's population; and consume about 78 percent of the world's energy. It is estimated, warned the expert, that in the next three decades almost 70 million people will migrate annually to urban areas, with the growing demand for services (water, transportation, energy) and social inequality.

She stated that Mexico is in 14th place among the countries with the highest greenhouse gas (GHG) emissions. Likewise, the National Inventory of Greenhouse Gas and Compound Emissions (INEGYCEI) 1990-2019 reveals that the main one is carbon dioxide (CO2) with 67 percent, followed by methane with 24 percent and nitrous oxide, six percent. In 2019, 736.63 million tons of CO2 were emitted in our country, and estimates of black carbon amounted to 65 thousand 582 tons.

To review air quality, recalled the specialist of the Institute of Atmospheric Sciences and Climate Change, the pandemic was an unplanned experiment, because there was the experience of seeing how, stopped the vehicle fleet, polluting emissions decreased, but you can not depend on this situation to reduce them. Regarding the actions implemented in this matter, he pointed out that it has been proposed to reduce the heat island by covering roofs in white to reflect light and solar radiation.

There are also the strategies promoted through the Climate Action Program of Mexico City 2021-2030, which involve mitigating 83 percent of greenhouse gas emissions by 2040 (over 2016 emissions). These measures include integrated and sustainable mobility, solar city, zero waste, sustainable water management and rescue of rivers and water bodies, revegetation from the countryside to the city, adaptive capacity and urban resilience, air quality, and climate culture.