If El Niño Wasn’t Responsible For East African Floods, What Was Then?

New study reveals El Niño not responsible for East African floods — climate change made them twice as likely and 5% more intense

Growing up, I was obsessed with East African landscapes. Cheetahs were, well, and still are, my favorite animals (together with sea turtles and penguins). I was the kid who chose nature documentaries over cartoons, and I never had enough fun facts about the Masai Mara. At the early age of five, I even told my mom I would move there eventually.

Fast-forward to the present day, and although I have been in Kenya for a conference and teaching about conservation, my dream didn’t materialize. Don’t get me wrong; I’m so happy with the life I chose and my scientific adventures everywhere else, but Kenya (or East Africa) didn’t happen.

However, the awe never dissipated, and even after years, I still believe my heart belongs in Kenya. So when I read the news about the devastating flood that swept through East Africa in 2023, killing over 500 people and displacing hundreds of thousands, I couldn’t help feeling extreme sadness. Homes were destroyed, roads became impassable, and entire communities were left to rebuild from scratch. Nothing left for them.

Many believed this disaster resulted from El Niño, a climate phenomenon known for causing dramatic weather changes worldwide. However, a new study by the World Weather Attribution (WWA) group reveals a different wrongdoer.

El Niño is a natural climate pattern characterized by warmer-than-average sea surface temperatures in the central and eastern Pacific Oceans. This phenomenon, which typically occurs every two to seven years, can disrupt weather patterns across the globe. In some regions, it brings drought; in others, it causes heavy rainfall and floods. Usually, the opposite to the climatological conditions a population has adapted to and built resilience around. Because El Niño is often linked to extreme weather, it was initially suspected to have played a role in East Africa’s severe floods.

The WWA study, however, found no evidence that El Niño or the Indian Ocean Dipole (IOD) influenced this year’s floods. The IOD, another climate phenomenon, involves temperature differences in the Indian Ocean, which can also affect regional weather patterns. Despite these potential influences, the study concluded that neither El Niño nor the IOD was responsible for the heavy rainfall experienced in East Africa.

Scientists reached this conclusion by analyzing weather data and climate models. They compared current rainfall patterns with those from the pre-industrial era to understand how various factors, including global warming, have altered these patterns over the years. I was happy to see they used this methodology in their study, as I have also used it in my own research.

Surprisingly, their findings showed no significant links between the current El Niño conditions and the recent flooding. Was this an isolated event, or did climate change impacts cause this?

Indeed, the study pointed to the usual suspect, climate change, as a significant driver behind the extreme rainfall. The data indicated that human-induced climate change has made such intense rainfall events twice as likely and five percent more intense than they would have been in a world without global warming. It turns out that as the planet warms, the atmosphere holds more moisture, leading to heavier rainfall during storms and monsoon seasons.

For those interested in the exact methodology and data collection, the study examined the maximum 30-day rainfall during the March to May monsoon season. Researchers found that the increased frequency and intensity of such rainfall events align with the predictions of climate models that account for global warming. This trend is expected to continue, making future floods even more devastating if no action is taken to prevent or mitigate them.

Unfortunately, the floods had a deep impact on East Africa. Lives, homes, and infrastructure were lost; the economic repercussions will be felt for years. The heavy rains in East Africa overwhelmed rivers, causing them to overflow. By the end of April 2024, over 27,717 acres of cropland were damaged due to the floods. Many affected regions had already been struggling with the aftermath of previous floods and droughts, making recovery extra hard this time.

Urban areas, especially informal settlements, were particularly vulnerable. These densely populated areas often lack adequate infrastructure for extreme weather, which can facilitate severe flooding and damage. As you can imagine, inadequate drainage systems and fragile building structures all contributed to the severity of the disaster.

Given these findings, addressing climate change is mandatory for reducing future flood risks. I’ve said this a million times already, but reducing greenhouse gas emissions and transitioning to renewable energy sources are important steps in slowing global warming. Immediate mitigation actions can help communities better prepare for and respond to extreme weather events.

Nonetheless, to do so, the already stretched-thin governments in East Africa will need to invest in reliable infrastructure to protect against future floods. Better drainage systems, reinforced riverbanks, and flood barriers are some of the adaptation strategies that could help manage the excess water from heavy rains. Additionally, future urban planning will need to take into account flood risks. This includes not building in flood-prone areas and improving the resilience of existing structures.

On the other hand, healthy ecosystems could play a significant role in mitigating flood impacts. Forests, wetlands, and mangroves act as natural protectors, absorbing excess water and reducing flood risks. Protecting and restoring these areas could enhance their ability to mitigate floods. For example, reforestation projects can help stabilize soil and improve water absorption, reducing the risk of landslides and floods. See the story below about the role mangrove forests could have on these measures.

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The most important thing, though, is that effective early warning systems can save lives by providing timely information about impending floods. Thus, these systems should be integrated into community planning, ensuring that residents receive alerts and know how to respond. Education campaigns can help communities understand the plans and risks and prepare accordingly. Community involvement is always the most powerful tool in catastrophe prevention.

In addition to physical infrastructure, social protection programs can help people recover more quickly from disasters. The study highlights how financial assistance, temporary housing, and food security programs can support people and families affected by floods. These programs can also help build resilience, helping communities bounce back more effectively from future events (which we hope are less damaging).

While East Africa experiences the consequences of these climate impacts, addressing climate change is a global responsibility. The region contributes only a small fraction to global carbon emissions but suffers some of the most severe consequences. Wealthier nations, with their larger carbon footprints, have a moral obligation to support climate adaptation and mitigation efforts in vulnerable regions. Read the latest IPCC report if you’d like to learn more about the initiatives being implemented at global and local scales. Also, you may want to look at the main takeaways from COP27, including the need for developed countries to support countries facing the most consequences from climate change.

The recent floods in East Africa highlight the urgent need to address climate change and invest in resilience. The WWA study clearly shows that human-induced climate change, not El Niño, is driving the increase in extreme weather events. Hopefully, East Africa can better prepare for future floods by improving infrastructure, protecting ecosystems, and implementing effective early warning systems. However, global action is needed to reduce emissions and support these efforts.

Only through collective action can we hope to mitigate the impacts of climate change and protect vulnerable communities worldwide. In the meantime, Kenya and East Africa will remain the most beautiful places on earth, deep in my heart, a place so meaningful for the ecological system as much as for the evolution of our species.