In a report to clients, the economists said that without action being taken, there could be catastrophic outcomes.
The bank said the research came from a team that was wholly independent from the company as a whole.
Climate campaigners have previously criticised JP Morgan for its investments in fossil fuels.
While JP Morgan economists have warned about unpredictability in climate change before, the language used in the new report was very forceful.
“We cannot rule out catastrophic outcomes where human life as we know it is threatened,” JP Morgan economists David Mackie and Jessica Murray said.
Carbon emissions in the coming decades “will continue to affect the climate for centuries to come in a way that is likely to be irreversible,” they said, adding that climate change action should be motivated “by the likelihood of extreme events”.
Climate change could affect economic growth, shares, health, and how long people live, they said.
It could put stresses on water, cause famine, and cause people to be displaced or migrate. Climate change could also cause political stress, conflict, and it could hit biodiversity and species survival, the report warned.
To mitigate climate change net carbon emissions need to be cut to zero by 2050. To do this, there needed to be a global tax on carbon, the report authors said.