Table 1.

Model parameters of soil respiration (natural log, in µmol C⋅m⁻²⋅s⁻¹) (R) as a function of soil temperature (T) (°C), evaluating the interaction with warming treatment

Parameters for model: ln(R) ∼ γ0 + γ1T + γ2T2
Model	γ0 ± SE	γ1 ± SE	γ2 ± SE	n	R2	T at R max
All biomes except desert					0.39
Control treatment	−1.292 ± 0.079	0.204 ± 0.011	−0.0042 ± 0.0003	1075		24.2
Warming treatment	−1.309 ± 0.119	0.205 ± 0.015	−0.0040 ± 0.0005	1268		25.3
Desert					0.42
Control treatment	−2.571 ± 0.062	0.019 ± 0.008	0.0004 ± 0.0002	737		na
Warming treatment	−3.431 ± 0.088	0.072 ± 0.011	−0.0007 ± 0.0003	737		55.4
Boreal forest					0.84
Control treatment	−0.063 ± 0.045	0.109 ± 0.0035	ns	160		na
Warming treatment	−0.010 ± 0.059	0.093 ± 0.0043	ns	306		na
Temperate forest					0.54
Control treatment	−0.813 ± 0.166	0.160 ± 0.024	−0.0025 ± 0.0008	239		32.0
Warming treatment	−1.485 ± 0.349	0.197 ± 0.042	−0.0031 ± 0.0012	258		31.8
Northern shrubland					0.63
Control treatment	−1.188 ± 0.081	0.142 ± 0.008	ns	172		na
Warming treatment	−1.153 ± 0.115	0.141 ± 0.012	ns	172		na
Southern shrubland					0.25
Control treatment	−1.420 ± 0.421	0.157 ± 0.040	−0.0027 ± 0.0009	51		29.1
Warming treatment	−0.485 ± 0.642	0.066 ± 0.061	−0.0010 ± 0.0013	51		34.4
Grassland					0.51
Control treatment	−1.517 ± 0.166	0.200 ± 0.024	−0.0036 ± 0.0006	269		27.8
Warming treatment	−1.558 ± 0.244	0.205 ± 0.030	−0.0036 ± 0.0008	297		28.7
Temperate agriculture					0.73
Control treatment	−3.012 ± 0.173	0.305 ± 0.030	−0.0066 ± 0.0012	131		23.3
Warming treatment	−3.091 ± 0.291	0.313 ± 0.046	−0.0065 ± 0.0016	131		24.2

Models run with data from both treatments, with parameters for each treatment calculated using the model equation. Model equation: $\ln \left(R\right)\approx \left({\alpha }_o+{\alpha }_{1}T+{\alpha }_2{T}^2\right)\hspace{0.17em}+\left({\beta }_o+{\beta }_{1}T+{\beta }_2{T}^2\right)\hspace{0.17em}W$, with γ_i = α_i + β_i. warming treatment (W = 1) or control treatment (W = 0). n, sample size; na, not applicable; ns, not significant; R², correlation coefficient; and T at R max, soil temperature (°C) when $d\ln \left(R\right)/dT=0$. Parameter units: γ₀, ln µmol C⋅m⁻²⋅s⁻¹; γ₁, °C⁻¹; and γ₂, °C⁻². Bold biome names indicate significant interactions with treatment. All models are significant (P < 0.001). For comparison of model fits, see SI Appendix, Table S3. For model parameters including moisture, see SI Appendix, Table S2.