Climate researchers at Oxford University have published a study in Nature Sustainability, according to which the population experiencing extreme heat is projected to “nearly double” by 2050 compared to 2010 levels.
According to the study, 41% of the global population will live in extreme heat regions by 2050, defined by the number and severity of cooling degree days, compared to 23% in 2010. This new data will be crucial for predicting energy demand for heating and cooling buildings as climate patterns change due to global warming. The data shows that heating demands will decline while cooling demands will increase as the average global temperature rises.
The data is essential for planning climate change adaptation, assessing geographic inequalities, and identifying vulnerable populations. According to the study, the 20 countries with the most drastic increase in cooling needs are all developing nations, with the Central African Republic, Nigeria, and South Sudan topping the chart, whose socioeconomic development will further suffer from global warming.
Most increases in cooling demand will occur by the time the planet reaches 1.5 degrees Celsius of warming compared to pre-industrial temperatures (i.e. within the first half a degree of global warming going forward).
The study used heating and cooling degree days as quantifiable representations of human response to global warming. Heating degree days refer to colder-than-usual temperatures, which prompt people to use heating technology such as radiators to warm buildings. Cooling degree days refer to the opposite – warmer temperatures that prompt the use of cooling technology like air conditioners. This benchmark also reflects the energy use and emissions associated with heating and cooling systems.
The researchers visualised the dataset with 30 different maps that depict heating degree days and cooling degree days around the world according to three hypothetical increases in the average global temperature: one degree Celsius, one and a half degrees Celsius and two degrees Celsius, each compared to a pre-industrial baseline. The average global temperature increased by about one degree Celsius between 2006 and 2016.
The data set is particularly flexible because it is temperature-dependent, rather than time-dependent: The results are not affected by when the warming happens, only by how much warming occurs. The findings are therefore especially helpful to policy-makers for planning, adapting, and preparing infrastructure in the face of uncertain futures; the data will remain relevant regardless of how quickly the planet warms.
The results can also pair with existing time-specific models of climate change. The researchers chose to cross-reference their data with Shared Socioeconomic Pathway (SSP) 2-4.5, a popular moderate prediction of future climate change which sees a decline in emissions – without reaching net-zero – by the end of the century.
The Oxford research team included lead author and Associate Professor in Engineering Science Jesus Lizana alongside Senior Researcher Nicole Miranda, Associate Professor in Environmental Impact Sarah Sparrow, Professor in Informatics David Wallom, Associate Professor Radhika Khosla, and Professor of Energy Systems Malcolm McCulloch.
