A study published in Environmental Research Letters estimates that greenhouse gases released from natural systems could amplify human-caused global warming by 20-30% by 2100. These emissions from permafrost, wetlands, freshwater, and wildfires could add an additional 0.2°-0.4° Celsius (0.4°-0.7° Fahrenheit) of warming.
Methane accounts for approximately half of this projected warming. The research focused on increased emissions released after 2020, as increased global temperatures accelerate decay in permafrost, microbial activity in wetlands and freshwater, and wildfire frequency in forests. This study was the first to combine these four sources to quantify their potential amplification of anthropogenic warming.
Source: Mongabay