A gradual change refers to climate changing slowly over time. The time intervals are in decades. Examples of gradual climate change include a global average temperature increase of 0.5 C over a 50 year time period, precipitation increasing 4% in a 30 year period as compared to a previous 30 year period, and sea level slowly rising by 0.5 meters over a 50 year period. Although gradual climate change can produce significant impacts, the impacts are gradual and it is easier to make adjustments as the change slowly takes place.

A tipping point/ immediate change refers to climate change that occurs abruptly and it has immediate and profound impacts on the climate. Within hours, days and months after the event, the climate will change significantly. The change can be so significant that the climate does not return back to the initial conditions before the tipping change. A tipping change can be thought of as an “on/off” switch. Instead of a gradual change, when the switch is flipped, the climate changes dramatically. Examples of tipping change include massive asteroid Earth collisions, massive alteration to global ocean current pattern, and supermassive volcanic eruptions. Both a massive asteroid and supermassive volcanic eruption will produce an immediate and profound global cooling. Great extinctions are possible in these situations. Ocean current pattern can suddenly change as continental drift occurs and precipitation/surface coverage of ice/salinity changes on the ocean. Although continents move only inches per year, it can be the case that once a continent moves to a critical position (along with other potential changes), the ocean currents will suddenly change. Since deep ocean currents often depend on salinity conditions, ice coverage pattern, and precipitation pattern on the ocean surface, changing these variables can cause an abrupt shift in the positions of cold and warm ocean currents. Since climate on land is a strong function of ocean current temperature, changing the temperature of the surface current will significantly change the climate over land.