Tuesday, November 11, 2008

Current warming sharpest climate change in 5,000 years: study

posted by Chris Irwin at 11:51 AM

2 Comments:

Anonymous Anonymous said...

Alright folks, extra heat energy means jet stream energy means extreme cold winter/extreme hot
summer.

Glaciers melting worldwide. Don't believe me?
http://www.ipcc.ch/pdf/technical-papers/ccw/chapter2.pdf


And:
http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf

[quote]1.1 Observations of climate change
Since the TAR, progress in understanding how climate is changing
in space and time has been gained through improvements and
extensions of numerous datasets and data analyses, broader geographical
coverage, better understanding of uncertainties and a wider
variety of measurements. {WGI SPM}
Definitions of climate change
Climate change in IPCC usage refers to a change in the state
of the climate that can be identified (e.g. using statistical tests)
by changes in the mean and/or the variability of its properties,
and that persists for an extended period, typically decades or
longer. It refers to any change in climate over time, whether
due to natural variability or as a result of human activity. This
usage differs from that in the United Nations Framework Convention
on Climate Change (UNFCCC), where climate change
refers to a change of climate that is attributed directly or indirectly
to human activity that alters the composition of the global
atmosphere and that is in addition to natural climate variability
observed over comparable time periods.
Warming of the climate system is unequivocal, as is now
evident from observations of increases in global average
air and ocean temperatures, widespread melting of snow
and ice and rising global average sea level (Figure 1.1). {WGI
3.2, 4.8, 5.2, 5.5, SPM}
Eleven of the last twelve years (1995-2006) rank among the
twelve warmest years in the instrumental record of global surface
temperature (since 1850). The 100-year linear trend (1906-2005)
of 0.74 [0.56 to 0.92]°C is larger than the corresponding trend of
0.6 [0.4 to 0.8]°C (1901-2000) given in the TAR (Figure 1.1). The
linear warming trend over the 50 years from 1956 to 2005 (0.13
[0.10 to 0.16]°C per decade) is nearly twice that for the 100 years
from 1906 to 2005. {WGI 3.2, SPM}
The temperature increase is widespread over the globe and is
greater at higher northern latitudes (Figure 1.2). Average Arctic temperatures
have increased at almost twice the global average rate in
the past 100 years. Land regions have warmed faster than the oceans
(Figures 1.2 and 2.5). Observations since 1961 show that the average
temperature of the global ocean has increased to depths of at
least 3000m and that the ocean has been taking up over 80% of the
heat being added to the climate system. New analyses of balloonborne
and satellite measurements of lower- and mid-tropospheric
temperature show warming rates similar to those observed in surface
temperature. {WGI 3.2, 3.4, 5.2, SPM}
Increases in sea level are consistent with warming (Figure 1.1).
Global average sea level rose at an average rate of 1.8 [1.3 to 2.3]mm
per year over 1961 to 2003 and at an average rate of about 3.1 [2.4
to 3.8]mm per year from 1993 to 2003. Whether this faster rate for
1993 to 2003 reflects decadal variation or an increase in the longerterm
trend is unclear. Since 1993 thermal expansion of the oceans
has contributed about 57% of the sum of the estimated individual
contributions to the sea level rise, with decreases in glaciers and
ice caps contributing about 28% and losses from the polar ice sheets
contributing the remainder. From 1993 to 2003 the sum of these
climate contributions is consistent within uncertainties with the total
sea level rise that is directly observed. {WGI 4.6, 4.8, 5.5, SPM, Table
SPM.1}
Observed decreases in snow and ice extent are also consistent
with warming (Figure 1.1). Satellite data since 1978 show that annual
average Arctic sea ice extent has shrunk by 2.7 [2.1 to 3.3]%
per decade, with larger decreases in summer of 7.4 [5.0 to 9.8]%
per decade. Mountain glaciers and snow cover on average have
declined in both hemispheres. The maximum areal extent of seasonally
frozen ground has decreased by about 7% in the Northern
Hemisphere since 1900, with decreases in spring of up to 15%.
Temperatures at the top of the permafrost layer have generally increased
since the 1980s in the Arctic by up to 3°C. {WGI 3.2, 4.5, 4.6,
4.7, 4.8, 5.5, SPM}
At continental, regional and ocean basin scales, numerous longterm
changes in other aspects of climate have also been observed.
Trends from 1900 to 2005 have been observed in precipitation
amount in many large regions. Over this period, precipitation increased
significantly in eastern parts of North and South America,
northern Europe and northern and central Asia whereas precipitation
declined in the Sahel, the Mediterranean, southern Africa and
parts of southern Asia. Globally, the area affected by drought has
likely2 increased since the 1970s. {WGI 3.3, 3.9, SPM}
Some extreme weather events have changed in frequency and/
or intensity over the last 50 years:
It is very likely that cold days, cold nights and frosts have become
less frequent over most land areas, while hot days and
hot nights have become more frequent. {WGI 3.8, SPM}
It is likely that heat waves have become more frequent over
most land areas. {WGI 3.8, SPM}
It is likely that the frequency of heavy precipitation events (or
proportion of total rainfall from heavy falls) has increased over
most areas. {WGI 3.8, 3.9, SPM}
It is likely that the incidence of extreme high sea level3 has
increased at a broad range of sites worldwide since 1975. {WGI
5.5, SPM}
There is observational evidence of an increase in intense tropical
cyclone activity in the North Atlantic since about 1970, and suggestions
of increased intense tropical cyclone activity in some other regions
where concerns over data quality are greater. Multi-decadal variability
and the quality of the tropical cyclone records prior to routine
satellite observations in about 1970 complicate the detection of longterm
trends in tropical cyclone activity. {WGI 3.8, SPM}
Average Northern Hemisphere temperatures during the second
half of the 20th century were very likely higher than during any other
50-year period in the last 500 years and likely the highest in at least
the past 1300 years. {WGI 6.6, SPM}
2 Likelihood and confidence statements in italics represent calibrated expressions of uncertainty and confidence. See Box ‘Treatment of uncertainty’ in the
Introduction for an explanation of these terms.
3 Excluding tsunamis, which are not due to climate change. Extreme high sea level depends on average sea level and on regional weather systems. It is
defined here as the highest 1% of hourly values of observed sea level at a station for a given reference period.[/quote]

Also: http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf
[quote]Causes of change
This Topic considers both natural and anthropogenic drivers of
climate change, including the chain from greenhouse gas (GHG)
emissions to atmospheric concentrations to radiative forcing4 to
climate responses and effects.
2.1 Emissions of long-lived GHGs
The radiative forcing of the climate system is dominated by the
long-lived GHGs, and this section considers those whose emissions
are covered by the UNFCCC.
Global GHG emissions due to human activities have grown
since pre-industrial times, with an increase of 70% between
1970 and 2004 (Figure 2.1).5 {WGIII 1.3, SPM}
Carbon dioxide (CO2) is the most important anthropogenic GHG.
Its annual emissions have grown between 1970 and 2004 by about
80%, from 21 to 38 gigatonnes (Gt), and represented 77% of total
anthropogenic GHG emissions in 2004 (Figure 2.1). The rate of
growth of CO2-eq emissions was much higher during the recent
10-year period of 1995-2004 (0.92 GtCO2-eq per year) than during
the previous period of 1970-1994 (0.43 GtCO2-eq per year). {WGIII
1.3, TS.1, SPM}
4 Radiative forcing is a measure of the influence a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system and
is an index of the importance of the factor as a potential climate change mechanism. In this report radiative forcing values are for changes relative to preindustrial
conditions defined at 1750 and are expressed in watts per square metre (W/m2).
5 Includes only carbon dioxide (CO2 ), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphurhexafluoride
(SF6), whose emissions are covered by the UNFCCC. These GHGs are weighted by their 100-year Global Warming Potentials (GWPs), using values
consistent with reporting under the UNFCCC.
6 This report uses 100-year GWPs and numerical values consistent with reporting under the UNFCCC.
7 Such values may consider only GHGs, or a combination of GHGs and aerosols.
Carbon dioxide-equivalent (CO2-eq) emissions and
concentrations
GHGs differ in their warming influence (radiative forcing) on
the global climate system due to their different radiative properties
and lifetimes in the atmosphere. These warming influences
may be expressed through a common metric based on
the radiative forcing of CO2.
• CO2-equivalent emission is the amount of CO2 emission
that would cause the same time-integrated radiative forcing,
over a given time horizon, as an emitted amount of a longlived
GHG or a mixture of GHGs. The equivalent CO2 emission
is obtained by multiplying the emission of a GHG by its
Global Warming Potential (GWP) for the given time horizon.6
For a mix of GHGs it is obtained by summing the equivalent
CO2 emissions of each gas. Equivalent CO2 emission is a
standard and useful metric for comparing emissions of different
GHGs but does not imply the same climate change
responses (see WGI 2.10).
• CO2-equivalent concentration is the concentration of CO2
that would cause the same amount of radiative forcing as a
given mixture of CO2 and other forcing components.7
Figure 2.1. (a) Global annual emissions of anthropogenic GHGs from 1970 to 2004.5 (b) Share of different anthropogenic GHGs in total emissions in 2004
in terms of CO2-eq. (c) Share of different sectors in total anthropogenic GHG emissions in 2004 in terms of CO2-eq. (Forestry includes deforestation.) {WGIII[/quote]
[size=200]How can an entire group of international, unbiased scientists be totally wrong
on global warming?[/size]

Go visit the Alaska cities where people
living there have noticed the unprecedented changes, or visit people by the
glaciers.

http://www.climatehotmap.org/
Look at the map.

[quote]FINGERPRINTS: Direct manifestations of a widespread and long-term trend toward warmer global temperatures
Heat waves and periods of unusually warm weather
Ocean warming, sea-level rise and coastal flooding
Glaciers melting
Arctic and Antarctic warming

HARBINGERS: Events that foreshadow the types of impacts likely to become more frequent and widespread with continued warming.
Spreading disease
Earlier spring arrival
Plant and animal range shifts and population changes
Coral reef bleaching
Downpours, heavy snowfalls, and flooding
Droughts and fires
The map of early warning signs clearly illustrates the global nature of climate changes. In its 2001 assessment, the Intergovernmental Panel on Climate Change (IPCC) concluded that, �an increasing body of observations gives a collective picture of a warming world and other changes in the climate system."

While North America and Europe—where the science is strongest—exhibit the highest density of indicators, scientists have made a great effort in recent years to document the early impacts of global warming on other continents. Our map update reflects this emerging knowledge from all parts of the world.

Although factors other than climate may have intensified the severity of some of the events on the map, scientists predict such problems will increase if emissions of heat-trapping gases are not brought under control.[/quote]


Also:
[quote]The IPCC Special Report on Emission Scenarios determines the range of future possible greenhouse gas concentrations (and other forcings) based on considerations such as population growth, economic growth, energy efficiency and a host of other factors. This leads a wide range of possible forcing scenarios, and consequently a wide range of possible future climates.

According to the range of possible forcing scenarios, and taking into account uncertainty in climate model performance, the IPCC projects a best estimate of global temperature increase of 1.8 - 4.0°C with a possible range of 1.1 - 6.4°C by 2100, depending on which emissions scenario is used. However, this global average will integrate widely varying regional responses, such as the likelihood that land areas will warm much faster than ocean temperatures, particularly those land areas in northern high latitudes (and mostly in the cold season). Additionally, it is very likely that heat waves and other hot extremes will increase.[/quote]

[img]http://www.ncdc.noaa.gov/img/climate/globalwarming/ar4-fig-spm-5.gif[/img]

7:59 PM  
Blogger Gordon McCabe said...

Rather than looking at greenhouse gases such as carbon dioxide as the problem, it is the production of infrared radiation by the Earth which is the problem to be solved. If one could release a compound en masse, either into the atmosphere, or deposited upon the surface of the Earth, which absorbs infrared radiation and re-emits it at visible wavelengths, then the radiation emitted by the Earth will pass unhindered through the greenhouse gases into space.

This requires a so-called 'Anti-Stokes' material: "When a phosphor or other luminescent material emits light, in general, it emits light according to Stokes' Law, which provides that the wavelength of the fluorescent or emitted light is always greater than the wavelength of the exciting radiation...Anti-Stokes materials typically absorb infrared radiation in the range of about 700 to about 1300 nm, and emit in the visible spectrum." A variety of Anti-Stokes phosphors, based on yttrium, exist for the conversion of infrared radiation into visible radiation.

Intriguingly, lanthanum hexaboride is already being used on a trial basis in office windows to absorb all but 5% of the incident infrared radiation...

5:28 PM  

Post a Comment

<< Home