Due to the worldwide outbreak of pandemic covid-19, 2020 7th International Conference on Environmental Systems Research was concerted to a video conference instead of being held physically in Sydney, Austria during 3-5 December, 2020 as scheduled. The participants all are all very supportive, who show their cooperation by sending over their recorded videos and share them with each other. We highly appreciated your understanding and cooperation given the special circumstances. We believe we'll all survive this health crisis and get back to our normal life soon. We look forward to seeing you all next year.