Table 4.
The Timing of the Neolithic Revolution and Historical vs. Contemporary Interseasonal Temperature Volatility
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | |
|---|---|---|---|---|---|---|---|---|
| Dependent Variable is Thousand Years Elapsed since the Neolithic Revolution | ||||||||
| Interseasonal Volatility and Mean of Seasonal Temperature for the: | ||||||||
| Historical Period (1500–1900) | Contemporary Period (1901–2000) | |||||||
| Temperature Volatility | 5.367*** (0.767) |
4.642*** (0.710) |
4.521*** (1.068) |
3.712*** (0.875) |
5.063*** (0.680) |
4.224*** (0.618) |
4.123*** (1.093) |
3.185*** (0.968) |
| Temperature Volatility Square | −0.402*** (0.061) |
−0.343*** (0.053) |
−0.354*** (0.077) |
−0.287*** (0.060) |
−0.389*** (0.055) |
−0.318*** (0.045) |
−0.335*** (0.079) |
−0.256*** (0.064) |
| Mean Temperature | 0.173** (0.061) |
0.145** (0.067) |
−0.047 (0.377) |
−0.088 (0.314) |
0.164** (0.062) |
0.127 (0.073) |
−0.124 (0.344) |
−0.191 (0.296) |
| Log Distance to Frontier | −0.054 (0.125) |
−0.100 (0.120) |
−0.176 (0.128) |
−0.239* (0.129) |
−0.002 (0.124) |
−0.079 (0.121) |
−0.157 (0.137) |
−0.256 (0.152) |
| Absolute Latitude | −0.096** (0.035) |
−0.096** (0.035) |
−0.203 (0.183) |
−0.204 (0.155) |
−0.106** (0.037) |
−0.107** (0.039) |
−0.248 (0.169) |
−0.259 (0.147) |
| Land Area | 1.589 (1.170) |
1.900* (1.005) |
2.972*** (0.853) |
3.301*** (1.062) |
1.360 (1.176) |
1.827* (1.020) |
2.789*** (0.872) |
3.282** (1.205) |
| Climate | −0.940 (0.541) |
−0.981 (0.627) |
−1.070* (0.573) |
−1.045 (0.683) |
||||
| Orientation of Landmass | 2.498*** (0.808) |
2.547** (0.968) |
2.168** (0.763) |
2.183** (0.926) |
||||
| Size of Landmass | −0.163*** (0.037) |
−0.148** (0.052) |
−0.144*** (0.034) |
−0.126** (0.050) |
||||
| Geographic Conditions | −0.787*** (0.213) |
−0.541** (0.237) |
−0.700*** (0.191) |
−0.424* (0.237) |
||||
| Mean Elevation | −0.318 (0.281) |
−0.349 (0.243) |
−0.344 (0.263) |
−0.394 (0.244) |
||||
| Mean Ruggedness | 0.302 (0.257) |
0.403 (0.234) |
0.275 (0.245) |
0.390 (0.233) |
||||
| Landlocked Dummy | No | No | Yes | Yes | No | No | Yes | Yes |
| Europe Dummy | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Optimal Temperature Volatility | 6.680*** (0.236) |
6.772*** (0.214) |
6.392*** (0.398) |
6.478*** (0.386) |
6.506*** (0.242) |
6.645*** (0.222) |
6.157*** (0.418) |
6.221*** (0.475) |
| F-test p-value | <0.001 | <0.001 | 0.002 | 0.001 | <0.001 | <0.001 | 0.004 | 0.001 |
| Observations | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
| Adjusted R2 | 0.90 | 0.89 | 0.90 | 0.89 | 0.89 | 0.89 | 0.90 | 0.89 |
Notes:
For the 1500–1900 time period, temperature volatility is the interseasonal standard deviation of seasonal temperature across 1,604 observations spanning this period, and mean temperature is the interseasonal average across these observations;
For the 1901–2000 time period, temperature volatility is the interseasonal standard deviation of seasonal temperature across 400 observations spanning this period, and mean temperature is the interseasonal average across these observations;
For the 1901–2000 time period, monthly temperature observations are first aggregated into seasonal ones, and since all countries in the sample appear in the Northern Hemisphere, the seasons are defined as follows: Spring (Mar-Apr-May), Summer (Jun-Jul-Aug), Autumn (Sep-Oct-Nov), Winter (Dec-Jan-Feb);
Geographic conditions is the first principal component of climate, and the size and orientation of the landmass;
The excluded continental category in all regressions is Asia;
The F-test p-value is from the joint significance test of the linear and quadratic terms of temperature volatility;
Heteroskedasticity robust standard error estimates are reported in parentheses;
The standard error estimate for the optimal temperature volatility is computed via the delta method;
*** denotes statistical significance at the 1% level, ** at the 5% level, and * at the 10% level.