The phrase "harmful impact" refers to the negative consequence or effect that something has on someone or something. It means that whatever is being talked about is causing damage, harm, or distress. Full definition
It's the only realistic and pragmatic solution to the potentially harmful impacts of anthropogenic climate change. (innovationfiles.org)
And some advanced biofuels can also avoid food competition and reduce harmful impacts on soil, water and wildlife if they are carefully managed and sustainably harvested. (nrdc.org)
It must also work out a recovery plan to control and reduce harmful impacts to the species, usually by controlling the activities that cause harm. (nytimes.com)