Researchers analysed land temperatures from all over the world and discovered that, although contributing only 2 percent of land warming between 1992 and 2019, urbanisation is still not the primary driver of climate change
A recent study found that, globally, urbanisation has been contributing more and more to continental warming in recent decades, particularly in Asia's rapidly developing regions and nations.
Researchers analysed land temperatures from all over the world and discovered that, although contributing only 2 percent of land warming between 1992 and 2019, urbanisation is still not the primary driver of climate change. It was discovered that India's urban areas had expanded by more than 350 percent.
According to Tirthankar C. Chakraborty and Yun Qian of Pacific Northwest National Laboratory in the US, urbanisation is typically disregarded when analysing historical data and predicting future climate for wide geographic areas because cities have historically occupied a relatively small portion of the Earth's surface.
The authors of the study, which was published in the journal One Earth, argued that urbanisation, along with land use changes, should be included in future climate change projections, whether at the local or continental scale.
Using satellite data, the researchers discovered that nearly 4.5 lakh square kilometres of urban land were added worldwide between 1992 and 2019.
The largest increases came from Asia (312 percent) and Africa (251 percent), while the smallest came from Oceania and other islands (155 percent), they said.
Over the same period, the Netherlands in Europe and Aruba in the Caribbean increased by more than 1,500 percent, while Iceland and Greenland remained virtually unchanged, according to the authors.
In countries with populations of more than 20 crore, the researchers discovered that China, the United States, and Brazil saw urban area growth of more than 400 percent, 180 percent, and 200 percent, respectively.
They said the growth in urban areas around the world -- from 0.26 percent to 0.6 percent -- is greater than that of the previous century.
As a result, as the world urbanises, its impact on climate change grows, despite being negligible in the 2000s, they said.
The researchers discovered that between 2003 and 2019, daytime temperatures in China's highly urbanised Shanghai metropolitan region rose by 0.4 degrees Celsius per decade, while night-time temperatures rose by 0.48 degrees Celsius per decade.
Europe was found to have the strongest daytime land surface temperature trends, which the authors speculated could be due to strong solar brightening during this time. Solar brightening is an increase in radiation reaching the Earth's surface.
On the contrary, China and India, which have experienced significant urbanisation and, as a result, strong trends in urban land surface temperatures, have shown little change in their overall land surface temperatures, which the researchers believe could be attributed to greening trends between 2003 and 2019.