Cyclone Chido was an “intense tropical cyclone”, equivalent to a category 4 hurricane in the Atlantic. It made landfall in Mayotte, a small island lying to the north-west of Madagascar on December 14, generating wind gusts approaching 155mph (250km/hr). Later on, it hit Mozambique, East Africa, with the same ferocity.
This storm skirted north of Madagascar and affected the Comoros archipelago before making landfall in Mozambique. It is well within the range of what is expected for this part of the Indian Ocean. But this region has experienced an increase in the most intense tropical cyclones in recent years. This, alongside its occurrence so early in the season, can be linked to increases in ocean temperatures as a result of climate change.
The risk that tropical cyclones pose to human life is exacerbated by socioeconomic issues. Migrants on Mayotte, many of whom made perilous journeys to escape conflict in countries such as the Democratic Republic of Congo, now make up more than half of the island’s population.
Precarious housing and the undocumented status of many residents reportedly made the disaster more deadly, as people feared evacuation would lead them to the police. On islands with poor infrastructure such as Mayotte, there is often simply nowhere safe to go. It takes many days for the power network and drinking water supply to be restored.
The situation is particularly complex in Mozambique. The ongoing conflict and terrorist violence, coupled with cyclones, including Kenneth in 2019, has caused repeated evacuations and worsening living conditions.
As of June 2024, more than half a million people remained without permanent homes in the region, many living in displacement camps. That number is likely to rise significantly after Chido.
The Indian Ocean is warming faster than the global average, and is experiencing a staggering increase in the proportion of storms reaching the intensity of Chido.
Climate simulations predict that storms will continue getting stronger as we further warm our world.
Scientists undertaking rapid attribution studies of Chido have found that the ocean surface temperatures along the path of the storm were 1.1°C warmer than they would have been without climate change. So, temperatures this warm were made more than 50 times more likely by climate change. Another study focusing on Chido itself concluded that the cyclone’s winds were 5% faster due to global heating caused by burning fossil fuels, enough to bump it from a category 3 to a category 4 storm.
Scientists are confident that tropical cyclones will dump more rain as a result of climate change. A trend towards slower-moving storms has been observed, causing more of that rain to accumulate in a single location, resulting in floods.
Cyclone Freddy delivered a year’s worth of rain to southern Malawi in just four days in March 2023. Storm surges, exacerbated by sea level rise, also raise the scale of flooding, as in the devastating Cyclone Idai in March 2019.