Fig. 2

Giant kelp, Macrocystis pyrifera, percent change relative to the 2004–2013 historical mean (%) before the extreme warming event (highlighted in red) for the northern and southern regions in the left y-axis. The black line indicates the average ± SE of the historical mean (2004–2013), the extreme warming event (2014–2016), and after the warming event (2017–2023). The red line indicates the average ± SE of the sea surface temperature for both regions in the right y-axis.