Sentences with phrase «multidecadal variability warming»

Not exact matches

Nonetheless, even if the substantial recent trend in the AO pattern is simply a product of natural multidecadal variability in North Atlantic climate, it underscores the fact that western and southern Greenland is an extremely poor place to look, from a signal vs. noise point of view, for the large - scale polar amplification signature of anthropogenic surface warming.

Here we demonstrate that the multidcadal variability in NHT including the recent warming hiatus is tied to the NAT - NAO - AMO - AMOC coupled mode and the NAO is implicated as a useful predictor of NHT multidecadal variability.

If you are trying to attribute warming over a short period, e.g. since 1980, detection requires that you explicitly consider the phasing of multidecadal natural internal variability during that period (e.g. AMO, PDO), not just the spectra over a long time period.

Since the CMIP5 models used by the IPCC on average adequately reproduce observed global warming in the last two and a half decades of the 20th century without any contribution from multidecadal ocean variability, it follows that those models (whose mean TCR is slightly over 1.8 °C) must be substantially too sensitive.

The AWP multidecadal variability coincides with the signal of the AMO; that is, the warm (cool) phases of the AMO are characterized by repeated large (small) AWPs.

Nonetheless, even if the substantial recent trend in the AO pattern is simply a product of natural multidecadal variability in North Atlantic climate, it underscores the fact that western and southern Greenland is an extremely poor place to look, from a signal vs. noise point of view, for the large - scale polar amplification signature of anthropogenic surface warming.

This study uses several independent data sources to demonstrate that century - long warming around the northeast Pacific margins, like multidecadal variability, can be primarily attributed to changes in atmospheric circulation.

Tropical North Atlantic SST has exhibited a warming trend of ~ 0.3 °C over the last 100 years; whereas Atlantic hurricane activity has not exhibited trendlike variability, but rather distinct multidecadal cycles as documented here and elsewhere.

The historical multidecadal - scale variability in Atlantic hurricane activity is much greater than what would be «expected» from a gradual temperature increase attributed to global warming.

Then when climategate triggered me to closely examine everything, notably the IPCC's attribution argument, I realized that the fingerprints were «muddy», the climate models are running too hot, the forcing data is uncertain, no account is made for multidecadal and longer internal variability, and they have no explanation for the warming 1910 - 1940, the cooling 1940 - 1976, and the hiatus since 1998.

In panel - b the magnitude of unforced variability is large (wide range between the blue lines) and thus changes in the multidecadal rate of warming could come about due to unforced variability.

Our results suggest that the decadal AO and multidecadal LFO drive large amplitude natural variability in the Arctic making detection of possible long - term trends induced by greenhouse gas warming most difficult.

Now forced to explain the warming hiatus, Trenberth has flipped flopped about the PDO's importance writing «One of the things emerging from several lines is that the IPCC has not paid enough attention to natural variability, on several time scales,» «especially El Niños and La Niñas, the Pacific Ocean phenomena that are not yet captured by climate models, and the longer term Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) which have cycle lengths of about 60 years.»

Multi-decadal oscillations plus trend hypothesis: 20th century climate variability / change is explained by the large multidecadal oscillations (e.g NAO, PDO, AMO) with a superimposed trend of external forcing (AGW warming).

«The global surface air temperature record of the last 150 years is characterized by a long ‐ term warming trend, with strong multidecadal variability superimposed.

It seems that every new climate scenario making the media over the past 20 years they always describe a warm future on a multidecadal scale ignoring a cool future as if variability didn't exist, but isn't scientific climatology primarily concerned with longer millenia time scales of a thousand years or more?

Recent accelerated warming of the Arctic results from a positive reinforcement of the linear warming trend (due to an increasing concentration of greenhouse gases and other possible forcings) by the warming phase of the multidecadal climate variability (due to fluctuations of the Atlantic Ocean circulation).»

The existence of the multidecadal variability makes climate change detection a challenge, since Global Warming evolves on a similar timescale.

The subtle shift toward warming during the past 15 years raises the question of whether the recent trends are linked more closely to anthropogenic influences or multidecadal variability.»

What was done, was to take a large number of models that could not reasonably simulate known patterns of natural behaviour (such as ENSO, the Pacific Decadal Oscillation, the Atlantic Multidecadal Oscillation), claim that such models nonetheless accurately depicted natural internal climate variability, and use the fact that these models could not replicate the warming episode from the mid seventies through the mid nineties, to argue that forcing was necessary and that the forcing must have been due to man.

iii) Even limiting any warming effect to the ocean skin and air above, it is utterly insignificant compared to natural variability from events such as El Nino / La Nina or from multidecadal variations in the levels of solar activity such as those from MWP to LIA to date.

A significant component of unforced multidecadal variability in the recent acceleration of global warming

The presence of multidecadal internal variability superimposed on the secular trend gives the appearance of accelerated warming and cooling episodes at roughly regular intervals.

The removal of the AMO in the determination of the anthropogenic warming trend is justified if one accepts our previous argument that this multidecadal variability is mostly natural.

Quantitatively, the recurrent multidecadal internal variability, often underestimated in attribution studies, accounts for 40 % of the observed recent 50 - y warming trend.

A focus of paleo reconstructions for the past 2000 years should be detecting multidecadal variability, rather than trying to convince that the recent decade is the warmest decade, etc..

The global surface air temperature record of the last 150 years is characterized by a long - term warming trend, with strong multidecadal variability superimposed.