The world recently experienced a 13-month streak of record-breaking global temperatures. And as blistering heat waves punish communities across several continents, 2024 is on track to be the hottest year on record. Global average temperatures are now perilously close to exceeding 1.5 degrees C (2.7 degrees F) above pre-industrial levels, a threshold scientists warn will bring increasingly dangerous droughts, wildfires and other impacts of climate change. Researchers project nearly 3 degrees C (5.4 degrees F) of temperature rise by 2100 without significant action to reduce greenhouse gas emissions.
That means almost 600 million people will be exposed to flooding from rising seas, food production will drop by as much as half and  habitats will suffer disastrous levels of loss. But what will 3 degrees C of warming vs. 1.5 degrees C look like in specific places — like Bengaluru, Johannesburg, Rio de Janeiro or the city you live in?
New data from WRI  finds that in most cities, the difference between 3 degrees C and 1.5 degrees C of warming is sizable. We analyzed potential climate hazards for nearly 1,000 of the world’s largest cities1 — currently home to 2.1 billion people, or 26% of the global population — using estimates based on downscaled global climate models. At 3 degrees C of warming, many cities could face month-long heat waves, skyrocketing energy demand for air conditioning, as well as a shifting risk for insect-borne diseases — sometimes simultaneously. People in low-income cities are likely to be the hardest hit.
These findings hold immense consequences for people’s lives and livelihoods, as well as for cities’ economies, infrastructure and public health systems. The implications are especially important as cities are home to 4.4 billion people globally — more than half the world’s population — and will grow rapidly over the next two decades. By 2050, as another 2.5 billion people move to urban areas, two-thirds of humanity will live in cities, with over 90% of that growth in Africa and Asia.
