(A) The Earth’s current state (globe shown in black) is nearing tipping point thresholds (within yellow band). The yellow dot depicts a tipping point threshold, and the blue and red vertical bands on the left and right of the graphs indicate troughs that represent relatively stable cooler or hothouse Earth states, respectively. Depending on the tipping threshold, a small increase in warming could still allow for a transition back to a cool, stabilized Earth (orange arrow in upper graph) or place the Earth system on a hothouse trajectory (orange arrow in lower graph). If a critical tipping point threshold is crossed at a relatively low temperature, then a hothouse trajectory could occur even assuming fairly low future emissions. The tipping point window reflects the uncertainty of the tipping point temperature threshold.
(B) Case study scenario of interconnected feedbacks and tipping cascades linking Arctic and Atlantic processes to the Amazon. Warming from greenhouse gas emissions accelerates Arctic sea ice and Greenland Ice Sheet loss, reducing albedo and adding meltwater that weakens the Atlantic Meridional Overturning Circulation. A weakened AMOC shifts tropical rainfall patterns, increasing drought risk and potential dieback in the northern Amazon forest, further amplifying global warming through the feedback involving carbon loss. Note that once one tipping point is crossed, it will likely impact the timing and temperature thresholds for other tipping points.
