Etter anbefaling fra Judith Curry viser vi i dag til to nye forskningsrapporter som i sum peker på at klimaet alltid har vært i endring, at det endrer seg i dag og at menneskets påvirkning på klimaet er minimal.
Varmere i Holeceneperioden
Først ut er en forskergruppe som i hovedsak er russisk, de har gått løs på torvlagene i Klukva i Tularegionen sørvest for Moskva hvor de har analysert en rekke proksier. Konklusjonen er at denne regionen hadde en langvarig varmetrend fra 9700 til 7500 år siden, med et skifte til det kjøligere klima vi har i dag for 5000 år siden. Quaternary Research 11.april 2015.
Holocene climatic variability and human impact on vegetation are reconstructed from a region in central European Russia, which lies at an important ecotone between broadleaf forest and steppe. For the first time in this region we adopt a multi-proxy approach that combines analysis of local mire conditions from plant macrofossil and testate amoeba analyses with pollen-based quantitative climate reconstruction. The proxies indicate a long-term warming trend from 9700 to 7500 cal yr BP, interrupted by a series of short-term cold events. From 7500 to 5000 cal yr BP the results imply a relatively stable climate, warmer and drier than present, spanning the Holocene Thermal Maximum. Since 5000 cal yr BP the data suggest a change to cooler climate, but with centennial-scale variability. This shift at around 5000 cal yr BP is supported by extensive evidence from other sites. In the early Holocene, the region was occupied mainly by pine and birch forests. Broad-leafed forests of oak, lime and elm expanded after 7800 cal yr BP and remained dominant until the last few centuries. During the historical period, vegetation changes have been driven mainly by human activities.
Hva skjer i Stillehavet?
Etter at NOAA nylig definerte en anelse varmere vann i deler av Stillehavet som starten på en ny El Ninjo, så har deler av klimaortodoksien vært fra seg av glede, inklusive vår hjemlige Terje Wahl som blogger fast på forskning.no og omsider har fått sitt ønske oppfylt. Enkelte trenger desperat fortgang i temperaturen før Klimasirkuset i Paris i desember og det hadde vært greitt å få til dette uten å måtte jukstere på temperaturmålingene for å kunne peke på en hundredels grad eller to. Men enkelte kjettere mer de ortodokse har solgt skinnet før sjøormen er skutt. Judith Curry har ingen tro på PDO (Pacific Decadal Oscillation) og henviser til “something else”:
Her fra Geophysical Research Letters hvor abstraktet lyder:
It is shown from historical data and from modeling experiments that a proximate cause of the cold winter in North America in 2013–2014 was the pattern of sea surface temperature (SST) in the Pacific Ocean. Each of the three dominant modes of SST variability in the Pacific is connected to the tropics and has a strong expression in extratropical SST and weather patterns. Beginning in the middle of 2013, the third mode of SST variability was two standard deviations positive and has remained so through January 2015. This pattern is associated with high pressure in the northeast Pacific and low pressure and low surface temperatures over central North America. A large ensemble of model experiments with observed SSTs confirms that SST anomalies contributed to the anomalous winter of 2014.
Samt denne fra Nature Climate Change hvor abstraktet er slik:
Despite a steady increase in atmospheric greenhouse gases (GHGs), global-mean surface temperature (T) has shown no discernible warming since about 2000, in sharp contrast to model simulations, which on average project strong warming1, 2, 3. The recent slowdown in observed surface warming has been attributed to decadal cooling in the tropical Pacific1, 4, 5, intensifying trade winds5, changes in El Niño activity6, 7, increasing volcanic activity8, 9, 10 and decreasing solar irradiance7. Earlier periods of arrested warming have been observed but received much less attention than the recent period, and their causes are poorly understood. Here we analyse observed and model-simulated global T fields to quantify the contributions of internal climate variability (ICV) to decadal changes in global-mean T since 1920. We show that the Interdecadal Pacific Oscillation (IPO) has been associated with large T anomalies over both ocean and land. Combined with another leading mode of ICV, the IPO explains most of the difference between observed and model-simulated rates of decadal change in global-mean T since 1920, and particularly over the so-called ‘hiatus’ period since about 2000. We conclude that ICV, mainly through the IPO, was largely responsible for the recent slowdown, as well as for earlier slowdowns and accelerations in global-mean T since 1920, with preferred spatial patterns different from those associated with GHG-induced warming or aerosol-induced cooling. Recent history suggests that the IPO could reverse course and lead to accelerated global warming in the coming decades.