The creation of puddled rice fields, covering around 3 million hectares, is believed to be a significant factor behind the climate shift in Punjab, according to a study.
Climate change is a global concern, but in Punjab, a state that plays a crucial role in India’s food security, a key factor driving regional climate shifts is the significant rise in rice cultivation, a new study has found. Over the past few decades, this change has profoundly affected the region’s weather patterns, resulting in fluctuations in key meteorological parameters, including the monsoon, temperature, humidity, evaporation rates, and sunshine hours.
The study conducted by three scientists from Punjab Agricultural University (PAU), Ludhiana, is titled ‘Rice Cultivation: A Contributor to Climate Change in Indian Punjab – A Perspective’. It was published in Theoretical and Applied Climatology journal on February 5.
Primarily conducted during the summer months but reflecting the year-round impact of climate on Punjab, the study reveals that the major shift toward rice cultivation began in the late 1960s with the advent of the ‘Green Revolution’. This shift, it says, transformed the central plains zone, which accounts for about 55 per cent of the state’s area and over 70 per cent of its rice-growing land in the summer. In contrast, the flanking zones, which are mainly devoted to vegetables, maize, and cotton, have lower rice coverage, as per the study.
According to the study, meteorological data from 1970 to 2020 shows that rice-intensive regions in the state have experienced a consistent rise in minimum daily temperatures of 0.054°C per year, while non-rice regions saw negligible changes.
The study conducted by Prabhjyot Kaur, principal scientist at the Department of Climate change and Agricultural Meteorology, PAU, along with Assistant Professor Harleen Kaur and N S Bains, former director of research at PAU, states that changes in temperature, humidity, and evaporation were most pronounced during the rapid expansion of rice cultivation between 1970 and 1995. The extensive creation of puddled rice fields, covering around 3 million hectares, is believed to be a significant factor behind these climate shifts. The study also explores how this sharp increase in rice acreage (up nearly 705 per cent in 50 years) might have altered monsoon rainfall patterns in the region.
Altered monsoon patterns
The study notes that in Punjab, the rice-growing season typically begins in the second week of June, with the transplantation of nurseries under puddled conditions, and the crop matures around the first week of October. During this period, the monsoon rains usually arrive in a brief window from late June to early July, closely aligning with the rice growth cycle. The monsoon typically withdraws by mid-September, just as the rice nears maturation.
However, since the early 2000s, Punjab has seen a significant shift toward rice-based agroecology, which has coincided with changes in the monsoon pattern, as per the study. Historically, the monsoon season in Punjab lasted around 77 days. But since 2000, it has been extending by an average of 0.8 days per year, reaching 98 days in 2020 and 118 days in 2021. Despite the longer duration, however, the total amount of rainfall has decreased, with an average annual decline of 6 mm. Over 21 years, from 2000 to 2020, rainfall during the monsoon was below normal in 18 years. In many of these years, rainfall was up to 20 per cent below normal, and in some cases, it exceeded a 20 per cent deficit.
