The last ice age ended about 11,700 years ago. It started almost 3 million years before that and was thought to have been caused by changes in the way that the Earth moved around the Sun.
So can we cause a new ice age? From this evidence it seems unlikely that we (humans) can cause a future ice age. With our production of greenhouse gases (Carbon Dioxide, Carbon Fluoride compounds and other related gases) it likely that we will be warming the atmosphere rather than making it colder. This may cause weather extremes which might make life on our planet (for humans) unacceptable. See the following link