Early Holocene Temperature Oscillations Exceed Amplitude of Observed and Projected Warming in Svalbard Lakes

by Van der Bilt et al. , December 3, 2019 in GeophysResLetters


Arctic climate is uniquely sensitive to ongoing warming. The feedbacks that drive this amplified response remain insufficiently quantified and misrepresented in model scenarios of future warming. Comparison with paleotemperature reconstructions from past warm intervals can help close this gap. The Early Holocene (11.7–8.2 ka BP) is an important target because Arctic temperatures were warmer than today. This study presents centennially resolved summer temperature reconstructions from three Svalbard lakes. We show that Early Holocene temperatures fluctuated between the coldest and warmest extremes of the past 12 ka, exceeding the range of instrumental observations and future projections. Peak warmth occurred ~10 ka BP, with temperatures 7 °C warmer than today due to high radiative forcing and intensified inflow of warm Atlantic waters. Between 9.5 and 8 ka BP, temperatures dropped in response to freshwater fluxes from melting ice. Facing similar mechanisms, our findings may provide insight into the near‐future response of Arctic climate.

It has been hotter, fires have burnt larger areas

by J. Marohasy, January 4, 2020 in WUWT

Last summer, and this summer, has been hot in Australia. But the summer of 1938-1939 was probably hotter — and back then more ferocious bushfires burnt larger areas. In rural Victoria, the summer of 1938-1939 was on average at least two degrees hotter than anything measured with equivalent equipment since, as shown in Figure 1.

Figure 1. Mean maximum summer (December, January February) temperatures as measured at Rutherglen in rural Victoria by The Australian Bureau of Meteorology for the period when mercury thermometers were used. Data unadjusted/not homogenised.

The summer of 1938-1939 was probably the hottest ever in recorded history for the states of New South Wales and Victoria. It is difficult to know for sure because the Bureau has since changed how temperatures are measured at many locations and has not provided any indication of how current electronic probes are recording relative to the earlier mercury thermometers.

Further, since 2011, the Bureau is not averaging measurements from these probes so the hottest recorded daily temperature is now a one-second spot reading from an electronic devise with a sheath of unknown thickness. In the United States similar equipment is used and the readings are averaged over five (5) minutes and then the measurement recorded.


See also: Australia Drought, The Indian Ocean Dipole & Sudden Stratospheric Warming

See also: Australia Bushfires – Is Blaming Greens a Conspiracy Theory?

See also : 24 People Charged For Setting Fires In New South Wales; Arrest Toll Hits 183