Greenhouse Effect: The three top greenhouses gases are; H2O, CO2 and CH4. They are greenhouse gases because it absorbs energy, thereby allowing less heat to escape back into space. When infrared light hits the gases, they reflect heat, which creates more photons. The greenhouse effect works when atmospheric gases, like carbon dioxide(CO2) absorbs energy from the sun, and when it is near Earth's surface, it gets "trapped" causing the Earth to warm to a temperature range that is suitable for life.
This shows data from 1850 and it show the outcome of it until 2100.
Feedback System: In this feedback system permafrost melts causing the release of methane. Carbon is released to the atmosphere in the form of methane, a powerful greenhouse gas. This process leads to climate change by warming causing more change which creates to more warming. This is a positive feedback because it is releasing a greenhouse gas, which is warming the Earth, it leads to more melting.
"...the IPCC estimates that by the mid-21st century, the area of permafrost in the northern hemisphere will decline by 20-35%. ... suggests the depth of thawing could increase by 30-50% by the year 2080."
"Permafrost comprises 24% of the land in the Northern Hemisphere, and stores massive amounts of carbon. As a result of climate change, permafrost is at risk of melting, releasing the stored carbon in the form of carbon dioxide and methane, which are powerful heat-trapping gases."
This is showing the difference between the Arctic Ocean in the years 2009-2010 and how much it has melted.