Three students have gone on hunger strike in a bid to force Cambridge University to stop investing in fossil fuel companies.
A further 25 students have also begun an occupation of Greenwich House, where many of the university's administrative offices are based.
The Cambridge Zero Carbon Society is demanding an "immediate commitment to full divestment from fossil fuels by the year 2022".
The protesters say action is needed to address a "climate emergency".
First-year undergraduates Sam Warren-Miell, Ben Margolis and one other began their hunger strike five days ago.
The society said it was "deeply proud" of their actions.
In addition to the hunger strike and occupation, 1,250 students have signed a petition calling for the divestment, while 350 academics have written an open letter to the university.