Deeper waters are changing less consistently than surface waters in a global analysis of 102 lakes

Table 3 Summary statistics of temporal trends for the thermal metrics across both time periods.

Thermal metric	Time period	Median slope	25th percentile	75th percentile	n lakes	% lakes increasing	% lakes decreasing
Surface water temperature (°C decade⁻¹)	1970–2009	0.37*	0.23	0.56	30	90%	7%
Surface water temperature (°C decade⁻¹)	1990–2009	0.33*	− 0.12	0.78	99	69%	29%
Deepwater temperature (°C decade⁻¹)	1970–2009	0.06	− 0.01	0.21	30	63%	27%
Deepwater temperature (°C decade⁻¹)	1990–2009	− 0.05	− 0.31	0.20	97	38%	54%
Mean water column temperature (°C decade⁻¹)	1970–2009	0.19*	0.09	0.30	30	87%	13%
Mean water column temperature (°C decade⁻¹)	1990–2009	0.05	− 0.22	0.27	97	54%	46%
Density difference (kg m⁻³ decade⁻¹)	1970–2009	0.08*	0.03	0.12	30	87%	13%
Density difference (kg m⁻³ decade⁻¹)	1990–2009	0.06*	− 0.02	0.18	97	69%	31%
Thermocline depth (m decade⁻¹)	1970–2009	0.03*	0.00	1.22	28	79%	18%
Thermocline depth (m decade⁻¹)	1990–2009	0.00	− 0.20	0.28	92	40%	47%

Summaries were based on Sen’s slopes from each individual lake. Asterisks indicate overall significant change across all lakes (1-sample Wilcoxon rank sum tests, p < 0.05). Percent of lakes increasing and decreasing represents all lakes, and does not necessarily add up to 100% due to a small percentage of lakes with a Sen’s slope of zero.