On balance the evidence shows that solar and oceanic variations are more likely the cause of recent observations of warming in the air than increasing CO2 in the air but the issue can soon be resolved by observing
the global air temperature changes that occur during and after the extended cycle 23 and the probable weak cycle 24.
If the sun is primarily responsible for observed
global air temperature changes (even if heavily modulated by ocean behaviour as I contend elsewhere) then we need to know sooner rather than later otherwise a misdiagnosis of the causes of climate change could cause unimaginable disruption and hardship through the imposition of incorrect remedies.
Partail statement: «The average
global air temperature changes as concentrations of CO2 in the atmosphere vary.»
Estimates of recent
global air temperature change don't show that.
I looked under the heading global temperatures list of contents and «Estimates of recent
global air temperature change» and it shows graphically exactly what your talking about.
Not exact matches
The map below shows the observed
change in
global near - surface
air temperature since 1900.
However, as climate
change raises
global air temperatures, it is possible that East Antarctic glaciers could start melting, a
change that could make the ice sheet shift back into unstable territory.
Water
changes temperature more slowly than the
air or land, which means the
global ocean heat is likely to persist for some time.
To remove this difference in magnitude and focus instead on the patterns of
change, the authors scaled the vertical profiles of ocean
temperature (area - weighted with respect to each vertical ocean layer) with the
global surface
air temperature trend of each period.
In the case of the
global temperature change caused by El Nino, there's still a «reason» for climate
change, to be found in the coupled
air - sea interaction..
Climate sensitivity is a measure of the equilibrium
global surface
air temperature change for a particular forcing.
-- Climate impacts:
global temperatures, ice cap melting, ocean currents, ENSO, volcanic impacts, tipping points, severe weather events — Environment impacts: ecosystem
changes, disease vectors, coastal flooding, marine ecosystem, agricultural system — Government actions: US political views, world - wide political views, carbon tax / cap - and - trade restrictions, state and city efforts — Reducing GHGs: + electric power systems: fossil fuel use, conservation, solar, wind, geothermal, nuclear, tidal, other + transportation sector: conservation, mass transit, high speed rail,
air travel, auto / truck (mileage issues, PHEVs, EVs, biofuels, hydrogen) + architectural structure design: home / office energy use, home / office conservation, passive solar, other
This was one of the motivations for our study out this week in Nature Climate
Change (England et al., 2014) With the
global - average surface
air temperature (SAT) more - or-less steady since 2001, scientists have been seeking to explain the climate mechanics of the slowdown in warming seen in the observations during 2001 - 2013.
Thus, small
changes of
global average
air temperature are associated with very large
changes in some regions, particularly over land, at mid - to high latitudes, in mountain regions.
ie does a slightly lower density of
air mean a slightly lower ground level
temperature (
temperature normally decreases with height at the lower
air density), so that in reality adding CO2 and subtracting more O2 actually causes miniscule or trivial
global COOLING, and the (unused) ability of the
changed atmosphere to absorb radiation energy and transmit it to the rest of the
air is overruled or limited by the ideal gas law?
Climate sensitivity is a measure of the equilibrium
global surface
air temperature change for a particular forcing.
I think it's a mistake to refer to
changes in
global average surface
air temperatures as if they were definitive measures of the
change to the climate system.
Re 9 wili — I know of a paper suggesting, as I recall, that enhanced «backradiation» (downward radiation reaching the surface emitted by the
air / clouds) contributed more to Arctic amplification specifically in the cold part of the year (just to be clear, backradiation should generally increase with any warming (aside from greenhouse feedbacks) and more so with a warming due to an increase in the greenhouse effect (including feedbacks like water vapor and, if positive, clouds, though regional
changes in water vapor and clouds can go against the
global trend); otherwise it was always my understanding that the albedo feedback was key (while sea ice decreases so far have been more a summer phenomenon (when it would be warmer to begin with), the heat capacity of the sea prevents much
temperature response, but there is a greater build up of heat from the albedo feedback, and this is released in the cold part of the year when ice forms later or would have formed or would have been thicker; the seasonal effect of reduced winter snow cover decreasing at those latitudes which still recieve sunlight in the winter would not be so delayed).
McIntyre has a new post where he tries to rescue the previous «projections» — but he confuses the
changes in HadSST (ocean
temperatures, which he is plotting) and the
changes in HadCRUT3 (the
global surface
air temperature anomaly) which is what his projection was for (as can be seen in the figures in the main post).
How can the ideal gas law predict a trivial
change in
temperature (due to the
change in
air density by substituting CO2 for oxygen) when the GCMs predict
global warming of 4 to 11 degrees?
If La Nina / El Nino can affect
global air temperatures in a period of a few years, than other
changes in ocean currents (driven by AGW) can affect
global atmospheric heat content in a few years.
The climate sensitivity is defined as the equilibrated
change in
global mean surface
air temperature (SAT) for a given
change in radiative forcing and has been a major focus of climate research over the last three decades.
The equilibrium climate sensitivity refers to the equilibrium
change in average
global surface
air temperature following a unit
change in the radiative forcing.
(3)
Changes in global atmospheric CO2 are lagging about 9.5 - 10 months behind changes in global surface air tempe
Changes in
global atmospheric CO2 are lagging about 9.5 - 10 months behind
changes in global surface air tempe
changes in
global surface
air temperature.
This is what most of us think of when we talk about «
Global Warming»; that it is
changes in the
air temperature!
Dana, I think you are pushing in the right direction with this; heat content is a much more direct measure of the underlying
changes to the climate system than average
air temperatures and climate science communicators should make heat content their first response to the suggestion that
global warming is something that waxes and (allegedly, recently) wanes.
Changing global temperatures induce
air circulation
changes as the
air seeks to restore the sea surface / surface
air temperature equilibrium...
The FAR used simple
global climate models to estimate
changes in the
global mean surface
air temperature under various CO2 emissions scenarios.
Global average surface air temperature is one of the most well - recognized metrics of contemporary climate change — hence the term «global warming&r
Global average surface
air temperature is one of the most well - recognized metrics of contemporary climate
change — hence the term «
global warming&r
global warming».
Sealing time of
air bubbles at best about 70 years and mixing with ambient
air through diffusion all that time, chemical
changes thereafter, different diffusion rates for different gases thereafter... ice cores are a target - rich environment for casting of doubt about how well they perform as
global temperature proxies.
Surface warming: «
Global temperature evolution: recent trends and some pitfalls» «Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends» «Recently amplified arctic warming has contributed to a continual global warming trend» «On the definition and identifiability of the alleged «hiatus» in global warming» «Global land - surface air temperature change based on the new CMA GLSAT dataset&
Global temperature evolution: recent trends and some pitfalls» «Coverage bias in the HadCRUT4
temperature series and its impact on recent
temperature trends» «Recently amplified arctic warming has contributed to a continual
global warming trend» «On the definition and identifiability of the alleged «hiatus» in global warming» «Global land - surface air temperature change based on the new CMA GLSAT dataset&
global warming trend» «On the definition and identifiability of the alleged «hiatus» in
global warming» «Global land - surface air temperature change based on the new CMA GLSAT dataset&
global warming» «
Global land - surface air temperature change based on the new CMA GLSAT dataset&
Global land - surface
air temperature change based on the new CMA GLSAT dataset»
Relationships between the
change in net top - of - atmosphere radiative flux, N, and
global - mean surface -
air -
temperature change, ΔT, after an instantaneous quadrupling of CO2.
The majority of power in the US comes from burning fossil fuels resulting in both
air quality problems and massive greenhouse gas emissions contributing to the rise of
global temperatures and climate
change.
Running 60 - month averages of
global air temperature at a height of two metres (left - hand axis) and estimated
change from the beginning of the industrial era (right - hand axis) according to different datasets: ERA - Interim (Copernicus Climate Change Service, ECMWF); GISTEMP (NASA); HadCRUT4 (Met Office Hadley Centre), NOAAGlobalTemp (NOAA); and JRA - 55
change from the beginning of the industrial era (right - hand axis) according to different datasets: ERA - Interim (Copernicus Climate
Change Service, ECMWF); GISTEMP (NASA); HadCRUT4 (Met Office Hadley Centre), NOAAGlobalTemp (NOAA); and JRA - 55
Change Service, ECMWF); GISTEMP (NASA); HadCRUT4 (Met Office Hadley Centre), NOAAGlobalTemp (NOAA); and JRA - 55 (JMA).
Ghil, 2013, explored the idea of abrupt climate
change with an energy balance climate model that follows the evolution of
global surface -
air temperature with
changes in the
global energy balance.
Maps show projected
change in average surface
air temperature in the later part of this century (2071 - 2099) relative to the later part of the last century (1970 - 1999) under a scenario that assumes substantial reductions in heat trapping gases (B1) and a higher emissions scenario that assumes continued increases in
global emissions (A2).
Internal variability can only account for ~ 0.3 °C
change in average
global surface
air temperature at most over periods of several decades, and scientific studies have consistently shown that it can not account for more than a small fraction of the
global warming over the past century.
I'm inclined to think that Ocean Heat Content, trends in land ice and Sea levels are more appropriate indicators of
global climate
change than surface
air temperatures, but that's another issue.
The NAO's prominent upward trend from the 1950s to the 1990s caused large regional
changes in
air temperature, precipitation, wind and storminess, with accompanying impacts on marine and terrestrial ecosystems, and contributed to the accelerated rise in
global mean surface
temperature (e.g., Hurrell 1996; Ottersen et al. 2001; Thompson et al. 2000; Visbeck et al. 2003; Stenseth et al. 2003).
The averaged surface
air temperature anomaly (dT) is widely recognised to be the most important index characterising the
global climate
changes including «
global warming» (Bell et al. 1998; Anisimov and Polyakov 1999).
Permafrost is very sensitive to direct
changes in
air temperature and snow cover, making it especially vulnerable to
global warming.
To point out just a couple of things: — oceans warming slower (or cooling slower) than lands on long - time trends is absolutely normal, because water is more difficult both to warm or to cool (I mean, we require both a bigger heat flow and more time); at the contrary, I see as a non-sense theory (made by some serrist, but don't know who) that oceans are storing up heat, and that suddenly they will release such heat as a positive feedback: or the water warms than no heat can be considered ad «stored» (we have no phase
change inside oceans, so no latent heat) or oceans begin to release heat but in the same time they have to cool (because they are losing heat); so, I don't feel strange that in last years land
temperatures for some series (NCDC and GISS) can be heating up while oceans are slightly cooling, but I feel strange that they are heating up so much to reverse
global trend from slightly negative / stable to slightly positive; but, in the end, all this is not an evidence that lands» warming is led by UHI (but, this effect, I would not exclude it from having a small part in
temperature trends for some regional area, but just small); both because, as writtend, it is normal to have waters warming slower than lands, and because lands»
temperatures are often measured in a not so precise way (despite they continue to give us a
global uncertainity in TT values which is barely the instrumental's one)-- but, to point out, HadCRU and MSU of last years (I mean always 2002 - 2006) follow much better waters»
temperatures trend; — metropolis and larger cities
temperature trends actually show an increase in UHI effect, but I think the sites are few, and the covered area is very small worldwide, so the
global effect is very poor (but it still can be sensible for regional effects); but I would not run out a small warming trend for airport measurements due mainly to three things: increasing jet planes traffic, enlarging airports (then more buildings and more asphalt — if you follow motor sports, or simply live in a town / city, you will know how easy they get very warmer than
air during day, and how much it can slow night - time cooling) and overall having airports nearer to cities (if not becoming an area inside the city after some decade of hurban growth, e.g. Milan - Linate); — I found no point about UHI in towns and villages; you will tell me they are not large cities; but, in comparison with 20-40-60 years ago when they were «countryside», many small towns and villages have become part of larger hurban areas (at least in Europe and Asia) so examining just larger cities would not be enough in my opinion to get a full view of UHI effect (still remembering that it has a small
global effect: we can say many matters are due to UHI instead of GW, maybe even that a small part of measured GW is due to UHI, and that GW measurements are not so precise to make us able to make good analisyses and predictions, but not that GW is due to UHI).
The latest climate science shows that in addition to climate mitigation, the world will need to remove carbon from the
air and store it if we are to have a good chance of achieving the
global goals of limiting
temperature rise to 1.5 - 2 degrees C (2.7 - 3.6 degrees F), the
temperature limit countries agreed to as part of the international Paris Agreement on climate
change.
An independent estimate of
global - mean evaporation provides additional support, but critical assumptions on relative humidity and the
air - sea
temperature difference
changes are made that do not have adequate observational basis and are inconsistent with climate models.»
Well, when we combine 20th century
global forcings with
air temperature changes in smaller areas we get the climate sensitivities shown below (note: these estimates are intended only to show the range of variation.
When we say «
global warming» what we're actually talking about here are the
air temperatures which, as one of the authors told me, is a relatively «fickle» measure of climate
change.
What the report says about climate
change and the Arctic: Over the past 50 years, near - surface
air temperatures across Alaska and the Arctic have increased at a rate more than twice as fast as the
global average.
The evidence comes from direct measurements of rising surface
air temperatures and subsurface ocean
temperatures and, indirectly, from increases in average
global sea levels, retreating glaciers, and
changes in many physical and biological systems.
The
global annual mean surface
air temperature change... centred at the time of CO2 doubling in a 1 % per year compound CO2 increase scenario.
Yet on these sites (and in the media, and even by a few semi related scientists who kinda keep an eye on the issue or are semi involved) treat it as if it is some sort of both immediate, and linear, contemporaneous correlation between increased lower level atmospheric re radiation, and increased (or
changed)
global ambient
air temperatures, which is absurd, and belies any real deep understanding of the actual issue.