Sunday, December 14, 2014

Scientific studies and information concerning the cooling NH winter trends

The pause in global warming, which is most evident from 1998-2014 (present) is actually due to a cooling trend for NH winters (boreal winter), which is most evident in January and February, which have such strong cooling trends, those two months alone bring the annual global mean down to an almost flat trend. Here it is in scientific lingo.

The largest discrepancy between observed and simulated trends in cold extremes is found in the Northern mid-latitudes (20 °N–45 °N), where observations indicate a coherent zonal band of decreasing trends over the recent 15 years. This might be connected to the recent hiatus in the warming of global Tmean, which has been characterized mainly as a winter phenomenon (e.g., Kosaka and Xie 2013, Cohen et al 2012). (source)

Observed and simulated temperature extremes during the recent warming hiatus (archived here)
Complete paper here (full paper pdf)

Shortwave and longwave radiative contributions to global warming under increasing CO2 (full paper pdf)

Trends in hemispheric warm and cold anomalies (full paper pdf)

Recent Arctic amplification and extreme mid-latitude weather (full paper pdf)

Arctic warming, increasing snow cover and widespread boreal winter cooling (full paper pdf)

Decadal Fluctuations in Planetary Wave Forcing Modulate Global Warming in Late Boreal Winter

Full paper (full paper pdf)

Improved Skill of Northern Hemisphere Winter Surface Temperature Predictions Based on Land–Atmosphere Fall Anomalies

Full paper (full paper pdf)

Asymmetric seasonal temperature trends (full paper pdf)

Ocean boreal winter trend

Ocean boreal summer trend

Land boreal winter trend

Land boreal summer trend

NCDC spring wheat belt trends winter summer

Tuesday, December 9, 2014

The Delaware river and climate change

William Curry is a serious, sober climate scientist, not an art critic. But he has spent a lot of time perusing Emanuel Gottlieb Leutze's famous painting "George Washington Crossing the Delaware," which depicts a boatload of colonial American soldiers making their way to attack English and Hessian troops the day after Christmas in 1776. "Most people think these other guys in the boat are rowing, but they are actually pushing the ice away," says Curry, tapping his finger on a reproduction of the painting. Sure enough, the lead oarsman is bashing the frozen river with his boot. "I grew up in Philadelphia. The place in this painting is 30 minutes away by car. I can tell you, this kind of thing just doesn't happen anymore." But it may again. Soon. And ice-choked scenes, similar to those immortalized by the 16th-century Flemish painter Pieter Brueghel the Elder, may also return to Europe. His works, including the 1565 masterpiece "Hunters in the Snow," make the now-temperate European landscapes look more like Lapland.

Discover article

Ice Jam Takes Delaware River to Flood Stage

By Dan Alexander January 9, 2014 2:18 PM

"Atmospheric Carbon Dioxide and Aerosols - Effects of Large Increases on Global Climate", Science, vol.173, 9 July 1971, p.138-141

ATMOSPHERIC CARBON DIOXIDE AND AEROSOLS:
Effects of Large Increases on Global Climate.

Abstract: Effects on the global temperature of large increases in carbon dioxide and aerosol densities in the atmosphere of Earth have been computed. It is found that, although the addition of carbon dioxide in the atmosphere does increase the surface temperature, the rate of temperature increase diminishes with increasing carbon dioxide in the atmosphere. For aerosols, however, the net effect of increase in density is to reduce the surface temperature of Earth. Becuase of the exponential dependence of the backscattering, the rate of temperature decrease is augmented with increasing aerosol content. An increase by only a factor of 4 in global aerosol background concentration may be sufficient to reduce the surface temperature by as much as 3.5 deg.K. If sustained over a period of several years, such a temperature decrease over the whole globe is believed to be sufficient to trigger an ice age.

The rate at which human activities may be inadvertently modifying the climate of Earth has become a problem of serious concern 1 . In the last few decades the concentration of CO2 in the atmosphere appears to have increased by 7 percent 2 . During the same period, the aerosol content of the lower atmosphere may have been augmented by as much as 100 percent 3 .

How have these changes in the composition of the atmosphere affected the climate of the globe? More importantly, is it possible that a continued increase in the CO2 and dust content of the atmosphere at the present rate will produce such large-scale effects on the global temperature that the process may run away, with the planet Earth eventually becoming as hot as Venus (700 deg. K.) or as cold as Mars (230 deg. K.)?

We report here on the first results of a calculation in which separate estimates were made of the effects on global temperature of large increases in the amount of CO2 and dust in the atmosphere. It is found that even an increase by a factor of 8 in the amount of CO2, which is highly unlikely in the next several thousand years, will produce an increase in the surface temperature of less than 2 deg. K.

However, the effect on surface temperature of an increase in the aerosol content of the atmosphere is found to be quite significant. An increase by a factor of 4 in the equilibrium dust concentration in the global atmosphere, which cannot be ruled out as a possibility within the next century, could decrease the mean surface temperature by as much as 3.5 deg. K. If sustained over a period of several years, such a temperature decrease could be sufficient to trigger an ice age!

Schneider S. & Rasool S., "Atmospheric Carbon Dioxide and Aerosols - Effects of Large Increases on Global Climate", Science, vol.173, 9 July 1971, p.138-141

(bolding is by yours truly)

Friday, December 5, 2014

Is ClimateCentral wrong?

ClimateCentral.org produced a research report claiming US winters are warming faster than ever (winter warming accelerated) and winters are warming faster than any other season. You can read the entire report by following the link. They used the NCDC US data available in 2012 for the report.

An example page from the report.

They describe the state of Alabama as the 48th fastest warming state , when their own chart shows even the hundred year trend is cooling. (-0.25F a decade)

(since 2012 the NCDC changed the data for the US, so that figure no longer matches the data at the NCDC)

The trend now shows as -0.1F a decade. How data gets changed.

There main claim in the report is that winter warming has accelerated, almost everywhere.

The current NCDC data shows this is not true, and summer warming is much greater than the winter trend. The twenty year trend shows this clearly.

US summer trend

US winter trend

This matches the NCDC data for the NH land trend, which also shows how summers are warming, but winters are in fact, cooling for the last twenty years (trend)

The thirty year trend for the US, as well as the NH land area, also shows winters are not warming as much as summers.

US winter trend

US summer trend

These are actual displays, right from the official NCDC. The thirty year trends for the NH land only also show this.

The GISS global data also clearly shows how boreal summers are warming faster than boreal winters,

GISS winter trend

30 years of data also shows the boreal (Northern Hemisphere) summer is warming faster than winter.

Basic Global warming theory says winters have to warm faster as CO2 level rise. You can see this sort of winter warming in the GISS image below, showing the trends for 1980-1998