Gday...

Global warming ?  Didn't ya hear - it has all gone now that we have had a change of government.

Cheers - John

I heard that due to over use and abuse the Greenie and scientific communities have withdrawn it from use.

They are at the moment in discussion into either renaming it to a more acceptable phrase or inventing a new terminology as they feel they have lost the ability to draw new grants and pensions etc from a near dead cause.

it may be the birth of global freezing or doomsday or some other name but they will after many grants and feasibility studies will find a new threat to our lifes so they can re apply for more grants and also have a way of gaining their overseas study tours etc.

For the time being we will return to our usual fluctuations in weather pattens that have existed for centuries with the ups and downs as our planet rotates around the sun and moves around our solar system and space.

So for any who were looking for global warming either move further north in the cool months or go to Kmart or Salvos and get another jumper.

Regards

Brian

beiffe wrote:

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I heard that due to over use and abuse the Greenie and scientific communities have withdrawn it from use.

They are at the moment in discussion into either renaming it to a more acceptable phrase or inventing a new terminology as they feel they have lost the ability to draw new grants and pensions etc from a near dead cause.

it may be the birth of global freezing or doomsday or some other name but they will after many grants and feasibility studies will find a new threat to our lifes so they can re apply for more grants and also have a way of gaining their overseas study tours etc.

For the time being we will return to our usual fluctuations in weather pattens that have existed for centuries with the ups and downs as our planet rotates around the sun and moves around our solar system and space.

So for any who were looking for global warming either move further north in the cool months or go to Kmart or Salvos and get another jumper.

Regards

Brian

 

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 I like it. 

aussietraveller wrote:

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just to ease the concern of other members I can confirm that someone bought it over here to Katherine but you would be most welcome to take it back JC there is a nice friendly couple leaving here tomorrow so they would probably help out, I am moving on to Darwin on Tuesday and certainly don't want it there

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  Leaving Archer Creek on tuesday for the run west over to the NT & then Nth, may catch up.

JC

Just in case you think that the globe is not warming...  

In all things, I tend to defer to the view of qualified experts rather than the oinions  other lay persons.. like myself

HOW WE KNOW GLOBAL WARMING IS REAL

Dr. Tapio Schneider discusses the science behind human-induced climate change. He is a climate scientist and Professor of Environmental Science and Engineering at the California Institute of Technology.

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The Science Behind Human-induced Climate Change

ATMOSPHERIC CARBON DIOXIDE CONCENTRATIONS are higher today than at any time in at least the past 650,000 years. They are about 35% higher than before the industrial revolution, and this increase is caused by human activities, primarily the burning of fossil fuels. Carbon dioxide is a greenhouse gas, as are methane, nitrous oxide, water vapor, and a host of other trace gases. They occur naturally in the atmosphere. Greenhouse gases act like a blanket for infrared radiation, retaining radiative energy near the surface that would otherwise escape directly to space. An increase in atmospheric concentrations of carbon dioxide and of other greenhouse gases augments the natural greenhouse effect; it increases the radiative energy available to Earths surface and to the lower atmosphere. Unless compensated for by other processes, the increase in radiative energy available to the surface and the lower atmosphere leads to warming. This we know. How do we know it?

Figure 1. Carbon dioxide concentrations in Antarctica over 400,000 years. The graph combines ice core data with recent samples of Antarctic air. The 100,000-year ice age cycle is clearly recognizable. (Data sources: Petit et al. 1999; Keeling and Whorf 2004; GLOBALVIEW-CO2 2007.)

How do we know carbon dioxide concentrations have increased?

The concentrations of carbon dioxide and other greenhouse gases in atmospheric samples have been measured continuously since the late 1950s. Since then, carbon dioxide concentrations have increased steadily from about 315 parts per million (ppm, or molecules of carbon dioxide per million molecules of dry air) in the late 1950s to about 385 ppm now, with small spatial variations away from major sources of emissions. For the more distant past, we can measure atmospheric concentrations of greenhouse gases in bubbles of ancient air preserved in ice (e.g., in Greenland and Antarctica). Ice core records currently go back 650,000 years; over this period we know that carbon dioxide concentrations have never been higher than they are now. Before the industrial revolution, they were about 280 ppm, and they have varied naturally between about 180 ppm during ice ages and 300 ppm during warm periods (Fig. 1). Concentrations of methane and nitrous oxide have likewise increased since the industrial revolution (Fig. 2) and, for methane, are higher now than they have been in the 650,000 years before the industrial revolution.

Figure 2. Greenhouses gases then and now.

How do we know the increase in carbon dioxide
concentrations is caused by human activities?

There are several lines of evidence. We know approximately how much carbon dioxide is emitted as a result of human activities. Adding up the human sources of carbon dioxide primarily from fossil fuel burning, cement production, and land use changes (e.g., deforestation) one finds that only about half the carbon dioxide emitted as a result of human activities has led to an increase in atmospheric concentrations. The other half of the emitted carbon dioxide has been taken up by oceans and the biosphere where and how exactly is not completely understood: there is a missing carbon sink.

Human activities thus can account for the increase in carbon dioxide concentrations. Changes in the isotopic composition of carbon dioxide show that the carbon in the added carbon dioxide derives largely from plant materials, that is, from processes such as burning of biomass or fossil fuels, which are derived from fossil plant materials. Minute changes in the atmospheric concentration of oxygen show that the added carbon dioxide derives from burning of the plant materials. And concentrations of carbon dioxide in the ocean have increased along with the atmospheric concentrations, showing that the increase in atmospheric carbon dioxide concentrations cannot be a result of release from the oceans. All lines of evidence taken together make it unambiguous that the increase in atmospheric carbon dioxide concentrations is human induced and is primarily a result of fossil fuel burning. (Similar reasoning can be evoked for other greenhouse gases, but for some of those, such as methane and nitrous oxide, their sources are not as clear as those of carbon dioxide.)

How can such a minute amount of carbon dioxide
affect Earths radiative energy balance?

Concentrations of carbon dioxide are measured in parts per million, those of methane and nitrous oxide in parts per billion. These are trace constituents of the atmosphere. Together with water vapor, they account for less than 1% of the volume of the atmosphere. And yet they are crucially important for Earths climate.

Earths surface is heated by absorption of solar (shortwave) radiation; it emits infrared (longwave) radiation, which would escape almost directly to space if it were not for water vapor and the other greenhouse gases. Nitrogen and oxygen, which account for about 99% of the volume of the atmosphere, are essentially transparent to infrared radiation. But greenhouse gases absorb infrared radiation and re-emit it in all directions. Some of the infrared radiation that would otherwise directly escape to space is emitted back toward the surface. Without this natural greenhouse effect, primarily owing to water vapor and carbon dioxide, Earths mean surface temperature would be a freezing -1°F, instead of the habitable 59°F we currently enjoy. Despite their small amounts, then, the greenhouse gases strongly affect Earths temperature. Increasing their concentration augments the natural greenhouse effect.

Figure 3. How We Know the Globe is Warming.

How do increases in greenhouse gas concentrations
lead to surface temperature increases?

Increasing the concentration of greenhouse gases increases the atmospheres optical thickness for infrared radiation, which means that more of the radiation that eventually does escape to space comes from higher levels in the atmosphere. The mean temperature at the level from which the infrared radiation effectively escapes to space (the emission level) is determined by the total amount of solar radiation absorbed by Earth. The same amount of energy Earth receives as solar radiation, in a steady state, must be returned as infrared radiation; the energy of radiation depends on the temperature at which it is emitted and thus determines the mean temperature at the emission level. For Earth, this temperature is -1°F the mean temperature of the surface if the atmosphere would not absorb infrared radiation. Now, increasing greenhouse gas concentrations implies raising the emission level at which, in the mean, this temperature is attained. If the temperature decreases between the surface and this level and its rate of decrease with height does not change substantially, then the surface temperature must increase as the emission level is raised. This is the greenhouse effect. It is also the reason that clear summer nights in deserts, under a dry atmosphere, are colder than cloudy summer nights on the U.S. east coast, under a relatively moist atmosphere (Figs. 4 and 5).

Figure 4 and 5. Two Cheers for the Greenhouse Effect. Some global warming is necessary in order to make the Earth habitable for creatures like us. These two graphics show how it works. The IPCC caption reads: Estimate of the Earths annual and global mean energy balance. Over the long term, the amount of incoming solar radiation absorbed by the Earth and atmosphere is balanced by the Earth and atmosphere releasing the same amount of outgoing longwave radiation. About half of the incoming solar radiation is absorbed by the Earths surface. This energy is transferred to the atmosphere by warming the air in contact with the surface (thermals), by evapotranspiration and by longwave radiation that is absorbed by clouds and greenhouse gases. The atmosphere in turn radiates longwave energy back to Earth as well as out to space. Source: Kiehl and Trenberth (1997). (Graphics are FAQ 1.1, 1.3, Figure 1 from the IPCC Report.)

In fact, Earth surface temperatures have increased by about 1.3°F over the past century (Fig. 3). The temperature increase has been particularly pronounced in the past 20 years (for an illustration, see the animations of temperature changes). The scientific consensus about the cause of the recent warming was summarized by the Intergovernmental Panel on Climate Change (IPCC) in 2007: Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations The observed widespread warming of the atmosphere and ocean, together with ice mass loss, support the conclusion that it is extremely unlikely that global climate change of the past 50 years can be explained without external forcing, and very likely that it is not due to known natural causes alone.

Figure 6. The History of Climate Models. The IPCC caption reads: The complexity of climate models has increased over the last few decades. The additional physics incorporated in the models are shown pictorially by the different features of the modelled world. (Graphic is Figure 1.2 from the IPCC Report.)

The IPCC conclusions rely on climate simulations with computer models (Fig. 6). Based on spectroscopic measurements of the optical properties of greenhouse gases, we can calculate relatively accurately the impact increasing concentrations of greenhouse gases have on Earths radiative energy balance. For example, the radiative forcing owing to increases in the concentrations of carbon dioxide, methane, and nitrous oxide in the industrial era is about 2.3 Watts per square meter. (This is the change in radiative energy fluxes in the lower troposphere before temperatures have adjusted.) We need computer models to translate changes in the radiative energy balance into changes in temperature and other climate variables because feedbacks in the climate system render the climate response to changes in the atmospheric composition complex, and because other human emissions (smog) also affect climate in complex ways. For example, as the surface and lower atmosphere warm in response to increases in carbon dioxide concentrations, the atmospheric concentration of water vapor near the surface increases as well. That this has to happen is well established on the basis of the energy balance of the surface and relations between evaporation rates and the relative humidity of the atmosphere (it is not directly, as is sometimes stated, a consequence of higher evaporation rates).

Water vapor, however, is a greenhouse gas in itself, and so it amplifies the temperature response to increases in carbon dioxide concentrations and leads to greater surface warming than would occur in the absence of water vapor feedback. Other feedbacks that must be taken into account in simulating the climate response to changes in atmospheric composition involve, for example, changes in cloud cover, dynamical changes that affect the rate at which temperature decreases with height and hence affect the strength of the greenhouse effect, and surface changes (e.g., loss of sea ice). Current climate models, with Newtons laws of motion and the laws of thermodynamics and radiative transfer at their core, take such processes into account. They are able to reproduce, for example, Earths seasonal cycle if all such processes are taken into account but not, for example, if water vapor feedback is neglected. The IPCCs conclusion is based on the fact that these models can only match the observed climate record of the past 50 years if they take human-induced changes in atmospheric composition into account. They fail to match the observed record if they only model natural variability, which may include, for example, climate responses to fluctuations in solar radiation (Fig. 7).

Figure 7. Global and Continental Temperature Change. The IPCC caption reads: Comparison of observed continental and global scale changes in surface temperature with results simulated by climate models using either natural or both natural and anthropogenic forcings. Decadal averages of observations are shown for the period 19062005 (black line) plotted against the center of the decade and relative to the corresponding average for the period 19011950. Lines are dashed where spatial coverage is less than 50%. Darker shaded bands show the 5 to 95% range for 19 simulations from five climate models using only the natural forcings due to solar activity and volcanoes. Lighter shaded bands show the 5 to 95% range for 58 simulations from 14 climate models using both natural and anthropogenic forcings. (Graphic is Figure SPM.4 from the IPCC Report.)

Climate feedbacks are the central source of scientific (as opposed to socio-economic) uncertainty in climate projections. The dominant source of uncertainty are cloud feedbacks, which are incompletely understood. The area covered by low stratus clouds may increase or decrease as the climate warms. Because stratus clouds are low, they do not have a strong greenhouse effect (the strength of the greenhouse effect depends on the temperature difference between the surface and the level from which infrared radiation is emitted, and this is small for low clouds); however, they reflect sunlight, and so exert a cooling effect on the surface, as anyone knows who has been near southern Californias coast on an overcast spring morning. If their area coverage increases as greenhouse gas concentrations increase, the surface temperature response will be muted; if their area coverage decreases, the surface temperature response will be amplified. It is currently unclear how these clouds respond to climate change, and climate models simulate widely varying responses. Other major uncertainties include the effects of aerosols (smog) on clouds and the radiative balance and, on timescales longer than a few decades, the response of ice sheets to changes in temperature.

Uncertainties notwithstanding, it is clear that increases in greenhouse gas concentrations, in the global mean, will lead to warming. Although climate models differ in the amount of warming they project, in its spatial distribution, and in other more detailed aspects of the climate response, all climate models that can reproduce observed characteristics such as the seasonal cycle project warming in response to the increases in greenhouse gas concentrations that are expected in the coming decades as a result of continued burning of fossil fuels and other human activities such as tropical deforestation. The projected consequences of the increased concentrations of greenhouse gases have been widely publicized. Global-mean surface temperatures are likely to increase by 2.0 to 11.5°F by the year 2100, with the uncertainty range reflecting scientific uncertainties (primarily about clouds) as well as socio-economic uncertainties (primarily about the rate of emission of greenhouse gases over the 21st century). Land areas are projected to warm faster than ocean areas. The risk of summer droughts in mid-continental regions is likely to increase. Sea level is projected to rise, both by thermal expansion of the warming oceans and by melting of land ice.

Less widely publicized but important for policy considerations are projected very long-term climate changes, of which some already now are unavoidable. Even if we were able to keep the atmospheric greenhouse gas concentration fixed at its present level this would require an immediate and unrealistically drastic reduction in emissions the Earth surface would likely warm by another 0.92.5°F over the next centuries. The oceans with their large thermal and dynamic inertia provide a buffer that delays the response of the surface climate to changes in greenhouse gas concentrations. The oceans will continue to warm over about 500 years. Their waters will expand as they warm, causing sea level rise. Ice sheets are thought to respond over timescales of centuries, though this is challenged by recent data from Greenland and Antarctica, which show evidence of a more rapid, though possibly transient, response. Their full contribution to sea level rise will take centuries to manifest. Studies of climate change abatement policies typically end in the year 2100 and thus do not take into account that most of the sea level rise due to the emission of greenhouse gases in the next 100 years will occur decades and centuries later. Sea level is projected to rise 0.20.6 meters by the year 2100, primarily as a result of thermal expansion of the oceans; however, it may eventually reach values up to several meters higher than today when the disintegration of glaciers and ice sheets contributes more strongly to sea level rise. (A sea level rise of 4 meters would submerge much of southern Florida.)

Certainties and Uncertainties

While there are uncertainties in climate projections, it is important to realize that the climate projections are based on sound scientific principles, such as the laws of thermodynamics and radiative transfer, with measurements of optical properties of gases. The record of past climate changes that can be inferred, for example, with geochemical methods from ice cores and ocean sediment cores, provides tantalizing hints of large climate changes that occurred over Earths history, and it poses challenges to our understanding of climate (for example, there is no complete and commonly accepted explanation for the cycle of ice ages and warm periods). However, climate models are not empirical, based on correlations in such records, but incorporate our best understanding of the physical, chemical, and biological processes being modeled. Hence, evidence that temperature changes precede changes in carbon dioxide concentrations in some climate changes on the timescales of ice ages, for example, only shows that temperature changes can affect the atmospheric carbon dioxide concentrations, which in turn feed back on temperature changes. Such evidence does not invalidate the laws of thermodynamics and radiative transfer, or the conclusion that the increase in greenhouse gas concentrations in the past decades is human induced.

The Author's biography ..

EEducation

1995-2000

Princeton University
Atmospheric and Oceanic Sciences Program (M.Sc. 1997, Ph.D. 2001)

1994-1995

University of Washington, Seattle
Visiting Graduate Student (Physics)

1991-1994

Albert-Ludwigs-Universität Freiburg, Germany
Studies of Mathematics and Physics (Vordiplom 1993)

Academic Employment

2013-present

Swiss Federal Institute of Technology Zurich, Department of Earth Sciences
Professor of Climate Dynamics

2002-present

California Institute of Technology, Environmental Science and Engineering
Director, Linde Center for Global Environmental Science (2011-2012)
Executive Officer for Environmental Science and Engineering (2011-2012)
Frank J. Gilloon Professor (2010-present)
Professor (2009-2010)
Associate Professor (2008-2009)
Assistant Professor (2002-2008)

2000-2002

New York University, Courant Institute of Mathematical Sciences
Associate Research Scientist

Selected Honors and Awards

2012

World Economic Forum, Annual Meeting of the New Champions, Tianjin, China (invited to participate as a "Young Scientist")

2010

Houghton Lecturer, Massachusetts Institute of Technology

2008

Science and Technology in Society Forum, Kyoto, Japan (selected to participate as 1 of 10 scientists under 40 worldwide)

2008

Discover Magazine Top 20 Scientists under 40

2005-2010

David and Lucile Packard Fellow

2004-2006

Alfred P. Sloan Research Fellow

2004

James R. Holton Junior Scientist Award, American Geophysical Union

1998-2000

NASA Earth System Science Fellow

1994-1998

Fellow of Studienstiftung des deutschen Volkes
(German National Scholarship Foundation)