A new study suggests that if greenhouse gas levels continue to rise, global warming could cause catastrophic heat waves across parts of India, Bangladesh and Pakistan. The analysis makes estimates of “wet bulb” temperature—a measure of heat and humidity, which when above  35°C becomes potentially fatal for healthy humans exposed to it for longer than six hours. Writing in Science Advances, the researchers describe projections of that measure across the south Asia subcontinent based on two of the planet’s less desirable future greenhouse gas levels, which the Intergovernmental Panel on Climate Change classifies as “intermediate” and  “high” scenarios. In the first case, huge areas of south Asia would regularly experience wet bulb temperatures above 31°C. In the second, many large regions—including India’s Ganges river valley, Pakistan’s Indus valley, and northern Sri Lanka—would experience wet bulb temperatures close to or exceeding 35°C.

What’s perhaps most troubling about the finding is that these regions are home to incredibly poor and vulnerable communities, which often make their living off of the land. That, of course, isn’t a new story: we recently reported that heat waves brought about climate change have already hit poor people the hardest, and we know that climate change will continue to drive global inequality in the future if it goes unchecked. But that doesn’t make it any less sad. As Chris Huntingford from the UK Centre for Ecology and Hydrology said to the Guardian: “If given just one word to describe climate change, then ‘unfairness’ would be a good candidate. Raised levels of carbon dioxide in the atmosphere are expected to cause deadly heatwaves for much of South Asia. Yet many of those living there will have contributed little to climate change.”