tipping point
... that the Amazon rainforest may change into a savanna once it passes a tipping point?
... that the <a href="./Amazon_rainforest" id="mwBeA" rel="mw:WikiLink" title="Amazon rainforest">Amazon rainforest</a> may change into a <a href="./Savanna" id="mwBeE" rel="mw:WikiLink" title="Savanna">savanna</a> once it passes a <b id="mwBeI"><a href="./Tipping_points_in_the_climate_system" id="mwBeM" rel="mw:WikiLink" title="Tipping points in the climate system">tipping point</a></b>?