Impact of climate change on Weeds and Weed management – A review

Climate change, mostly indicated by Global Warming is resultant of increasing greenhouse gases like CO2, Methane, N2O, Ozone, CFC etc. Atmospheric CO2 has already risen from 285 ppm to 380 ppm during the 20th century with observed increase from 1950s. Scientists agree that the planet’s temperature has risen by 0.5 degree Celsius since 1900 and will continue to increase at an increasing rate. The sea level has been rising at the rate of 2mm a year since the beginning of 20th century. Droughts and floods have become more common. Changes in climatic factors would alter the nature of vegetation and agriculture and it is true especially with the increasing atmospheric CO2 concentration. Most of the earth’s plants respond positively to the atmospheric CO2 enrichment by increasing their photosynthetic rates and biomass production. It is the point of contention, however, that weeds may be more responsive to the ongoing rise in atmospheric CO2 than non-weeds, and therefore they may increase their dominance in agro-ecosystems. In this situation, weeds compete with crops for nutrient, water and light and can considerably reduce yields and quality of crops. In some cases, weeds can pose a human health problem or cause disturbance to the harvest. Hence, the impacts of climate change on weeds and weed management practices are more important aspects in future as that of crop cultivation.