A controversial new study claims we may breach the 2 degrees Celsius (3.6 degrees Fahrenheit) climate change increase threshold by the late 2020s — almost two decades earlier than current projections.

The study, published Feb. 5 in the journal Nature Climate Change, claims global surface temperatures had increased by 1.7 C (3 F) above pre-industrial averages by the year 2020.

However, other scientists have questioned the findings, saying that there are major flaws in the work.