Last year, torrential rains swept across the Horn of Africa, displacing more than 234,000 people across Kenya, Somalia, Burundi and Tanzania.
In Dadaab, one of Somalia’s largest refugee camps, the consequences of this crisis are especially evident. There, Hamed, a 33-year-old woman, received a devastating diagnosis: she and her children had contracted tuberculosis (TB) again. In the camp’s crowded and sweltering conditions, the disease had found fertile ground to spread. Hamed additionally faced a new possibility; that her strain of tuberculosis is multi-drug resistant. Whether treatment will succeed is uncertain.
In 2024, tuberculosis reclaimed its title as the world’s leading infectious killer, surpassing COVID-19. The same year was officially the hottest year on record, with projected temperatures still worsening. The reality is stark. Tuberculosis is a climate-sensitive disease, and our warming world is fuelling its spread.
While diseases like malaria, dengue, and cholera have been associated with climate variability, TB is often not mentioned, even though it thrives in conditions of poverty, overcrowding and malnutrition. These risk factors are worsened by climate change. In fact, projections from Latin America highlight that climate change could increase the incidence of TB by 14-45 per cent in major cities.
Recognizing this gap in current efforts, the World Health Organization (WHO) held a two-day consultation on TB and climate change last October. Matteo Zignol, head of WHO’s global tuberculosis program, stated that while climate change has emerged as “one of the hottest topics in global health,” TB is “off the radar in climate change debates.” There are three significant ways climate change can exacerbate the spread of TB, (1) migration and displacement, (2) food and water insecurity and (3) health-system disruption.
There are now more people displaced by climate change than conflict, with approximately 60,000 people displaced every day due to climate change. We may have 1.2 billion climate refugees by 2050 based on projections. And as climate-related displacement increases, so too does the number of people exposed to TB, and the number of people with TB unable to access or complete treatment.
As climate-related displacement increases, so too does the number of people exposed to TB.
There are hundreds of thousands of climate refugees in Bangladesh, a country with the sixth highest TB rates globally. In Dhaka, its capital, thousands of climate refugees live in cramped, closed quarters with inadequate hygiene, fuelling the spread of TB. More than 1,060 people testing positive for TB in Dhaka in the first six months of 2024 were new arrivals that fled home due to rains and floods.
Climate change contributes to rising rates of food insecurity and malnutrition, which is the leading risk factor for TB, increasing the risk of TB two-fold in the short term. Initial projections warn that a two Celsius degree rise in global temperatures could translate to 189 million people who starve. With a four C increase, this could reach 1.8 billion people, more than 20 times Canada’s population. The most vulnerable are especially at risk, whether it be the Global South or Indigenous communities in the North.
The Intergovernmental Panel on Climate Change (IPCC) has warned that infectious diseases, including TB, are likely to increase in both incidence and severity due to climate change. Yet, despite this evidence, climate and TB are still largely treated as separate issues in health policy.
The global health community must respond. This means incorporating climate resilience into TB strategies, including strengthening health systems in vulnerable regions, ensuring access to diagnosis and treatment during emergencies and addressing the root social determinants that climate change exacerbates.
Hamed’s story is not in isolation. She is one of more than 320,000 people living in Dadaab’s Refugee Complex, where food insecurity, poor sanitation and disease outbreaks are growing more severe. With floods in Pakistan, cyclones in Madagascar and droughts in Somalia, her experience is a warning of what lies ahead if we fail to recognize the critical links between climate change and disease.
