Figure: Climate change will affect a large number of people

Brazil has experienced four floods in less than a year. The most recent one was on the 29th of last month, when torrential rains triggered floods and landslides in Rio Grande do Sul, Brazil, resulting in at least 155 deaths, more than 800 injuries and 620000 forced to leave their homes. Authorities said this was the worst disaster in the history of South Rio Grande. According to the analysis, this flood may create the largest climate refugee in Brazil's modern history, and hundreds of thousands of people were forced to leave their homes and move to "high places".

On April 29, southern Brazil suffered the worst flood in 83 years. In less than ten days, the rainfall in Rio Grande do Sul reached 300 mm, nearly half of the predicted annual rainfall. The continuous rainstorm caused the water level of the Guaiba River, which flows through the state capital, Porto Alegre, to rise to 5.35 meters, reaching a historical peak, and burst its banks, flooding many urban blocks.

Reconstruction cost exceeds 28.9 billion yuan

Rio Grande do Sul is the southernmost state in Brazil, with a population of nearly 11 million. It is one of the most prosperous states and an important crop production base. The state has experienced two floods in September and November last year, and suffered record losses. On the 17th of this month, Eduardo Wright, governor of Rio Grande do Sul, said that the reconstruction cost would be "much higher" than his initial estimate of 19 billion reais (about 28.9 billion Hong Kong dollars), and the situation might become worse.

Over the past three weeks, the death toll from floods in Rio Grande do Sul has increased every day. Experts warn that it will take at least two more weeks for the water level to fall. More than 77000 displaced persons still live in public shelters. The authorities plan to build four temporary "tent cities" to accommodate them, but many residents are still trapped in low-lying flooded areas waiting for rescue.

According to the statistics of the state civil defense department, more than two-thirds of 497 cities in Rio Grande do Sul were affected by floods and other disasters, and 46 of 96 residential areas in Porto Alegre, the capital of the state, were flooded. Even residents in areas not flooded have to endure several days of power and water cuts.

The Brazilian geological department said that the severity of the flood had exceeded the historical flood in 1941, and the water level in some areas had reached the highest level since records were kept for nearly 150 years. Five of the seven major rivers in the state are still above the highest water level.

The house is like a damaged toy

Environmental experts warned that, given the extent of the damage caused by the flood, reconstruction is no longer feasible, "the whole city (Porto Alegre) will have to change its location". Gabriel Sosa, Deputy Governor of Rio Grande do Sul, said to the local media on the 16th, "We are facing a series of challenges. We must move the whole city away from the original place, that is, rebuild the city in other places."

According to Reuters, a businessman living in Musum, a town 150 kilometers upstream of Porto Alegre, decided to move away from the river after three floods in seven months. He and his family had climbed onto the roof of their two-story house in the flood last September to wait for rescue until midnight. The house of another woman in the town was washed away by the flood last September, and the house she rented was also flooded in this round of flood. She said that it was difficult to live in this small town, and the rich people had already left. "These houses look like toys torn apart by children," said a local photographer in the heavily affected city of Takuri.

Climate refugees may break 200 million

Scientists say that the rare extreme flood in South Rio Grande is caused by climate factors. Southern Brazil is located at the intersection of tropical and very low ocean currents, where strong wind currents lead to climate instability. El Nino has warmed the Pacific waters, made central Brazil more arid and made heavy rainfall more frequent in the south.

Alex Randall, project leader of the Climate Outreach Organization and climate driven migration expert, pointed out that "most of the migration and displacement caused by climate change will occur in China." He added that as climate disasters become more frequent and extreme, more people will inevitably lose their homes.

Climate refugees, sometimes referred to as climate migrants, refer to people forced to be displaced by climate and environmental changes such as extreme weather, drought or flood. Most of them come from the southern hemisphere and countries with low economic levels. According to the migration data portal, at least 7.7 million people in 82 countries and regions are internally displaced due to climate disasters. The World Bank estimates that as many as 216 million people will become climate refugees by 2050. (Comprehensive report)