The right - hand panel shows ranges
of global average temperature change above pre-industrial, using (i) «best estimate» climate sensitivity of 3 °C (black line in middle of shaded area), (ii) upper bound of likely range of climate sensitivity of 4.5 °C (red line at top of shaded area)(iii) lower bound of likely range of climate sensitivity of 2 °C (blue line at bottom of shaded area).
As a result, I've followed the common practice of making a rough estimate
of global average temperature changes by dividing the Vostok changes in half.
Not exact matches
We have much better — and more conclusive — evidence for climate
change from more boring sources like
global temperature averages, or the extent
of global sea ice, or thousands
of years» worth
of C02 levels stored frozen in ice cores.
WHEREAS, in furtherance
of the united effort to address the effects
of climate
change, in 2010 the 16th Session
of the Conference
of the Parties to the UNFCC met in Cancun, Mexico and recognized that deep cuts in
global greenhouse gas emissions were required, with a goal
of reducing
global greenhouse gas emissions so as to hold the increase in
global average temperature below 2 °C above pre-industrial levels;
WHEREAS, in furtherance
of the united effort to address the effects
of climate
change, in 2015 the 21st Session
of the Conference
of the Parties to the UNFCC met in Paris, France and entered into a historic agreement in which 195 nations, including the United States, were signatories and agreed to determine their own target contribution to mitigate climate
change by holding the increase in the
global average temperature to well below 2 °C above pre-industrial levels and to pursue efforts to limit the
temperature increase to 1.5 °C above pre-industrial levels, among other terms (the «Paris Agreement»);
«This Agreement, in enhancing the implementation
of the [2015 United Nations Framework Convention on Climate
Change], including its objective, aims to strengthen the global response to the threat of climate change, in the context of sustainable development and efforts to eradicate poverty, including by: (a) Holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change; (b) Increasing the ability to adapt to the adverse impacts of climate change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production; and (c) Making finance flows consistent with a pathway towards low greenhouse gas emissions and climate - resilient develo
Change], including its objective, aims to strengthen the
global response to the threat
of climate
change, in the context of sustainable development and efforts to eradicate poverty, including by: (a) Holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change; (b) Increasing the ability to adapt to the adverse impacts of climate change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production; and (c) Making finance flows consistent with a pathway towards low greenhouse gas emissions and climate - resilient develo
change, in the context
of sustainable development and efforts to eradicate poverty, including by: (a) Holding the increase in the
global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the
temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts
of climate
change; (b) Increasing the ability to adapt to the adverse impacts of climate change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production; and (c) Making finance flows consistent with a pathway towards low greenhouse gas emissions and climate - resilient develo
change; (b) Increasing the ability to adapt to the adverse impacts
of climate
change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production; and (c) Making finance flows consistent with a pathway towards low greenhouse gas emissions and climate - resilient develo
change and foster climate resilience and low greenhouse gas emissions development, in a manner that does not threaten food production; and (c) Making finance flows consistent with a pathway towards low greenhouse gas emissions and climate - resilient development.
On Dec. 12, 2015, the 21st Conference
of the Parties to the U.N. Framework Convention on Climate
Change approved the Paris Agreement committing 195 nations
of the world to «holding the increase in the
global average temperature to well below 2 °C above preindustrial levels and pursuing efforts to limit the
temperature increase to 1.5 °C.»
January's mark
of 1.4 °C, put the
global average temperature change from early industrial levels for the first three months
of 2016 at 1.48 °C.
The
average global temperature change for the first three months
of 2016 was 1.48 °C, essentially equaling the 1.5 °C warming threshold agreed to by COP 21 negotiators in Paris last December.
Published today in the journal Nature Geoscience, the paper concludes that limiting the increase in
global average temperatures above pre-industrial levels to 1.5 °C, the goal
of the Paris Agreement on Climate
Change, is not yet geophysically impossible, but likely requires more ambitious emission reductions than those pledged so far.
The strength and path
of the North Atlantic jet stream and the Greenland blocking phenomena appear to be influenced by increasing
temperatures in the Arctic which have
averaged at least twice the
global warming rate over the past two decades, suggesting that those marked
changes may be a key factor affecting extreme weather conditions over the UK, although an Arctic connection may not occur each year.
MELBOURNE, AUSTRALIA — In the run - up to national elections on 21 August, the country's top science body, the Australian Academy
of Science (AAS), has weighed in on the climate
change debate with a report backing the mainstream scientific view that human - induced climate
change is real and that a business - as - usual approach to carbon emissions will lead to a «catastrophic» four - to five - degree increase in
average global temperatures.
Laaksonen and his colleagues did not try to predict how Finland's
temperatures will
change in the coming decades, but according to the U.N. Intergovernmental Panel on Climate Change's latest report, Arctic temperatures are likely to continue rising faster than the global average through the end of the 21st ce
change in the coming decades, but according to the U.N. Intergovernmental Panel on Climate
Change's latest report, Arctic temperatures are likely to continue rising faster than the global average through the end of the 21st ce
Change's latest report, Arctic
temperatures are likely to continue rising faster than the
global average through the end
of the 21st century.
Results
of a new study by researchers at the Northeast Climate Science Center (NECSC) at the University
of Massachusetts Amherst suggest that
temperatures across the northeastern United States will increase much faster than the
global average, so that the 2 - degrees Celsius warming target adopted in the recent Paris Agreement on climate
change will be reached about 20 years earlier for this part
of the U.S. compared to the world as a whole.
Of course, while short - term changes in sea level can be predicted fairly accurately based on the motions of the moon and sun, it is a lot harder predicting the ups and downs of the average global surface temperature — there is a lot of noise, or natural variation, in the syste
Of course, while short - term
changes in sea level can be predicted fairly accurately based on the motions
of the moon and sun, it is a lot harder predicting the ups and downs of the average global surface temperature — there is a lot of noise, or natural variation, in the syste
of the moon and sun, it is a lot harder predicting the ups and downs
of the average global surface temperature — there is a lot of noise, or natural variation, in the syste
of the
average global surface
temperature — there is a lot
of noise, or natural variation, in the syste
of noise, or natural variation, in the system.
But the U.K. Met Office (national weather service), the U.S.'s National Center for Atmospheric Research and other partners around the globe aim to
change that in the future by developing regular assessments — much like present evaluations
of global average temperatures along with building from the U.K. flooding risk modeling efforts — to determine how much a given season's extreme weather could be attributed to human influence.
Although the rising
average global surface
temperature is an indicator
of the degree
of disruption that we have imposed on the
global climate system, what's actually happening involves
changes in circulation patterns,
changes in precipitation patterns, and
changes in extremes.
But even with such policies in place — not only in the U.S. but across the globe — climate
change is a foregone conclusion;
global average temperatures have already risen by at least 1.1 degrees Fahrenheit (0.6 degree C) and further warming
of at least 0.7 degree F (0.4 degree C) is virtually certain, according to the IPCC.
Threats — ranging from the destruction
of coral reefs to more extreme weather events like hurricanes, droughts and floods — are becoming more likely at the
temperature change already underway: as little as 1.8 degree Fahrenheit (1 degree Celsius)
of warming in
global average temperatures.
Since the 19th century, sea level has shot up more than 2 millimeters per year on
average, far faster than other periods
of global temperature change.
This is defined as the
change in
average global surface
temperature for a given amount
of carbon dioxide accumulated in the atmosphere.
These rising atmospheric greenhouse gas concentrations have led to an increase in
global average temperatures of ~ 0.2 °C decade — 1, much
of which has been absorbed by the oceans, whilst the oceanic uptake
of atmospheric CO2 has led to major
changes in surface ocean pH (Levitus et al., 2000, 2005; Feely et al., 2008; Hoegh - Guldberg and Bruno, 2010; Mora et al., 2013; Roemmich et al., 2015).
However, at the increased levels seen since the Industrial Revolution (roughly 275 ppm then, 400 ppm now; Figure 2 - 1), greenhouse gases are contributing to the rapid rise
of our
global average temperatures by trapping more heat, often referred to as human - caused climate
change.
Third, using a «semi-empirical» statistical model calibrated to the relationship between
temperature and
global sea - level
change over the last 2000 years, we find that, in alternative histories in which the 20th century did not exceed the
average temperature over 500-1800 CE,
global sea - level rise in the 20th century would (with > 95 % probability) have been less than 51 %
of its observed value.
* Surface
temperature changes relative to 20th Century
global average (1901 - 2000) Source data NOAA - NCEI State of the Climate: Global Analysis [Web + data dow
global average (1901 - 2000) Source data NOAA - NCEI State
of the Climate:
Global Analysis [Web + data dow
Global Analysis [Web + data download]
A small
change in
average global temperature leads to a dramatic
change in the frequency
of extreme events.23 24 25 The following graphs in Figure 5 help to illustrate this point.
In effect, the HadCrut4 and NOAA GlobalTemp
global series simplistically assume
temperature change in the Arctic and other missing areas matches on
average that measured in the rest
of the globe.
Figure 1: Annual
global temperature change (thin light red) with 11 year moving
average of temperature (thick dark red).
[2] According to the Intergovernmental Panel on Climate
Change (IPCC), most
of the observed increase in
global average temperatures since the mid-20th century is very likely due to the observed increase in human greenhouse gas concentrations.
• 2 to 4.5 °C is lifting range that must suffer the
global average temperature by the end
of this century according to estimates made by the UN IPCC - Intergovernmental Panel on Climate
Change.
Human induced trend has two components, namely (a) greenhouse effect [this includes
global and local / regional component] and (b) non-greenhouse effect [local / regional component]-- according to IPCC (a) is more than half
of global average temperature anomaly wherein it also includes component
of volcanic activities, etc that comes under greenhouse effect; and (b) contribution is less than half — ecological
changes component but this is biased positive side by urban - heat - island effect component as the met network are concentrated in urban areas and rural - cold - island effect is biased negative side as the met stations are sparsely distributed though rural area is more than double to urban area.
... Polar amplification explains in part why Greenland Ice Sheet and the West Antarctic Ice Sheet appear to be highly sensitive to relatively small increases in CO2 concentration and
global mean
temperature... Polar amplification occurs if the magnitude
of zonally
averaged surface
temperature change at high latitudes exceeds the globally
averaged temperature change, in response to climate forcings and on time scales greater than the annual cycle.
But because
of the necessary caveats that must be applied due to the state
of the science I am starting to feel unable to say much about climate
change apart from: «The increase in CO2 will very probably cause an overall increase in
Global Average Temperature.
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.
Action on climate
change needs to be scaled up and accelerated without delay if the world is to have a running chance
of keeping a
global average temperature rise below 2 degrees Celsius this century.
We can not afford to delay further action to tackle climate
change if the long - term target
of limiting the
global average temperature increase to 2 °C, as analysed in the 450 Scenario, is to be achieved at reasonable cost.
Global average surface
temperatures are not expected to
change significantly although
temperatures at higher latitudes may be expected to decrease to a modest extent because
of a reduction in the efficiency
of meridional heat transport (offsetting the additional warming anticipated for this environment caused by the build - up
of greenhouse gases).
If one postulates that the
global average surface
temperature tracks the CO2 concentration in the atmosphere, possibly with some delay, then when the CO2 concentration continues to rise monotonically but the
global average surface
temperature shows fluctuations as a function
of time with
changes in slope (periods wherein it decreases), then you must throw the postulate away.
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.
Nonetheless, there is a tendency for similar equilibrium climate sensitivity ECS, especially using a Charney ECS defined as equilibrium
global time
average surface
temperature change per unit tropopause - level forcing with stratospheric adjustment, for different types
of forcings (CO2, CH4, solar) if the forcings are not too idiosyncratic.
I regularly speak to public audiences about climate
change (see http://www.andrewgunther.com/climate-
change/#talks for details), and use the NASA / GISS dataset to discuss
global average temperature of the atmosphere.
When it does end, they expect to see some rapid
changes, including a sudden acceleration
of global average surface
temperatures.
The efficacy
of a forcing is the climate sensitivity (in terms
of global average surface
temperature change per unit
global average RF)
of that forcing relative to a standard type
of forcing.
Starting from an old equilbrium, a
change in radiative forcing results in a radiative imbalance, which results in energy accumulation or depletion, which causes a
temperature response that approahes equilibrium when the remaining imbalance approaches zero — thus the equilibrium climatic response, in the
global - time
average (for a time period long enough to characterize the climatic state, including externally imposed cycles (day, year) and internal variability), causes an opposite
change in radiative fluxes (via Planck function)(plus convective fluxes, etc, where they occur) equal in magnitude to the sum
of the (externally) imposed forcing plus any «forcings» caused by non-Planck feedbacks (in particular, climate - dependent
changes in optical properties, + etc.).)
(PS we are considering the climate sensitivity to be in terms
of changes in
global - time
average surface
temperature per unit
global - time
average radiative forcing, though one could also define other sensitivities for other measures
of climate).
The standstil
of global average temperature predicted by the «improved» modell compared to warming predicted from the «old» modell is nothing that happens in the future, it should have happened (but did not happen) in the past, from 1985 to 1999: The «improved» modell (green graph) shows that the
global average temperature did not
change from 1985 (= mean 1980 - 1990) to 1999 (= mean 1994 to 2004).
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.
Redistribution
of heat (such as vertical transport between the surface and the deeper ocean) could cause some surface and atmospheric
temperature change that causes some
global average warming or cooling.
Pachauri started by saying that they «clearly ignored» the IPCC's recommendations on how to prevent climate
change, and then laid into the G8: Though it was a good thing that the G8 agreed to the aspirational goal
of limiting
global average temperature rise to 2 °C by 2050, Pachauri said he found it «interesting» that the G8 then proceeded to pay no heed to when the IPCC says carbon emissions should peak.
Recognizes that warming
of the climate system is unequivocal and that most
of the observed increase in
global average temperatures since the mid twentieth century is very likely due to the increase in anthropogenic greenhouse gas concentrations, as assessed by the Intergovernmental Panel for Climate
Change in its Fourth Assessment Report;