Sentences with phrase «ice age climate sensitivity»

«Third, in a period when ocean basins were similar to modern, ice age climate sensitivity to pCO2 changes is underestimated by climate models even when long term changes in solar forcing and ice sheet size and distribution are taken into account, implying that internal positive feedbacks are stronger than previously thought.»

Not exact matches

The ends of ice ages were different, but we can still use them to learn more about the sensitivity of the massive Antarctic ice sheet to climate change.»

If the high climate sensitivity effect of the ice ages is a result of the hysteresis effect as proposed by Oerlemans and Van den Dool (1978), then the present observed sensitivity of 1K / 2xCO2 can not be much higher.

Indeed, the main quandary faced by climate scientists is how to estimate climate sensitivity from the Little Ice Age or Medieval Warm Period, at all, given the relative small forcings over the past 1000 years, and the substantial uncertainties in both the forcings and the temperature changes.

A sensitivity which is too low will be inconsistent with past climate changes - basically if there is some large negative feedback which makes the sensitivity too low, it would have prevented the planet from transitioning from ice ages to interglacial periods, for example.

If the high climate sensitivity effect of the ice ages is a result of the hysteresis effect as proposed by Oerlemans and Van den Dool (1978), then the present observed sensitivity of 1K / 2xCO2 can not be much higher.

We contended here before that this is a bit of a leap, since there are other constraints on climate sensitivity (such as the last ice age) and other sources of uncertainty (solar, ozone, land use, etc.).

It seems that the ice age climate constraining a 2xCO2 doubling Climate Sensitivity is dependent on the assumption that the sensitivity is linear in the entire range of CO2 values from ice age levels (much below present) to 2x preindustrial climate constraining a 2xCO2 doubling Climate Sensitivity is dependent on the assumption that the sensitivity is linear in the entire range of CO2 values from ice age levels (much below present) to 2x preindustrial Climate Sensitivity is dependent on the assumption that the sensitivity is linear in the entire range of CO2 values from ice age levels (much below present) to 2x preindustrSensitivity is dependent on the assumption that the sensitivity is linear in the entire range of CO2 values from ice age levels (much below present) to 2x preindustrsensitivity is linear in the entire range of CO2 values from ice age levels (much below present) to 2x preindustrial values.

The Last Glacial Maximum (i.e. the most recent «ice age», abbreviated LGM) probably provides the best opportunity for using the past to constrain climate sensitivity.

An important takeaway point from this is that with a low climate sensitivity (i.e. one with limited positive feedbacks, or counterbalancing negative feedbacks), then the ice ages can't happen.

Indeed, the main quandary faced by climate scientists is how to estimate climate sensitivity from the Little Ice Age or Medieval Warm Period, at all, given the relative small forcings over the past 1000 years, and the substantial uncertainties in both the forcings and the temperature changes.

Second, the relationship we are seeing in the ice cores is made up of two independent factors: the sensitivity of the CO2 to temperature over the ice age cycle — roughly ~ 100 ppmv / 4ºC or ~ 25 ppmv / ºC — and the sensitivity of the climate to CO2, which we'd like to know.

We can study ice ages to approximate climate sensitivity, which indicate a value consistent with the accepted value of about 2 - 4 °C per doubling of CO2.

There are variuos ways to estimate climate sensitivity, studies of volcanic eruptions, ice ages, or measurements of Earth's energy budget.

I don't think he's predicting a mini ice age, but he is adamant that the assumptions about climate sensitivity to CO2 built into the climate models are wrong and the models grossly understate the importance of cosmic radiation.

(I'd guess they would be meaningless) And for climate sensitivity calculations (from both 20th C temp record and forcings, and; ice age and interglacial terminations, milankovitch cycles)?

Their reconstruction suggested that ocean temperatures varied less from today's value than one might have thought for an ice age, an indicator of relatively low climate sensitivity.

His research involves studies of the role of the tropics in mid-latitude weather and global heat transport, the moisture budget and its role in global change, the origins of ice ages, seasonal effects in atmospheric transport, stratospheric waves, and the observational determination of climate sensitivity.

``... the moisture budget and its role in global change, the origins of ice ages, seasonal effects in atmospheric transport, stratospheric waves, and the observational determination of climate sensitivity -LSB-...] the development of the current theory for the Hadley Circulation, -LSB-...] the quasi-biennial oscillation of the tropical stratosphere.

In short, the MARGO data for the ocean show very small temperature change from the ice age to today, and thus lead to the low climate sensitivity, but they disagree with some independent estimates showing larger temperature change.

Some of them deny it is even warming, others claim anthropogenic global warming (AGW) is a hoax, others claim that there is some magical negative feedback that will result in virtually no warming, others like Lewis cherry pick literature to delude themselves into thinking that climate sensitivity is low, while others are convinced that an ice age is imminent;)

Since after 38 years we still don't know the climatic effect of doubling CO2 concentrations (climate sensitivity), I think it is premature to declare the Ice Age dead.

Tags: earth system sensitivity, glacial, ice age, interglacial, Paleoclimate, Snyder, temperature reconstruction, two million years Posted in Climate science, English, Scenarios 4 Comments»

That's climate sensitivity, more or less — we got a few ice age cycles that have had roughly the same climate sensitivity.

Radiative forcing and response of a GCM to ice age boundary conditions: cloud feedback and climate sensitivity

Climate sensitivity is constrained by measurements, e.g. of the climate response to volcanoes and the last iClimate sensitivity is constrained by measurements, e.g. of the climate response to volcanoes and the last iclimate response to volcanoes and the last ice age.

Perhaps you could address what I consider to be most crucually wrong with your claims: — Such a low sensitivity (0.5 deg) is incompatible with measurements — With such a low sensitivity you can not explain the large climate changes that have occurred in Earth» history, e.g. the ice ages.

See Gavin Schimidt, «Why correlations of CO2 and temperature over ice age cycles don't define climate sensitivity,» RealClimate.org, Sept. 24, 2016, online here.

We study climate sensitivity and feedback processes in three independent ways: (1) by using a three dimensional (3 - D) global climate model for experiments in which solar irradiance So is increased 2 percent or CO2 is doubled, (2) by using the CLIMAP climate boundary conditions to analyze the contributions of different physical processes to the cooling of the last ice age (18K years ago), and (3) by using estimated changes in global temperature and the abundance of atmospheric greenhouse gases to deduce an empirical climate sensitivity for the period 1850 - 1980.

In fact, climate scientists have used paleoclimate data such as that for the ice ages to show that climate sensitivity is likely to be close to the range the IPCC favors.

The great thing is that, since we can make good estimates of the changes in solar radiation, changes in the Earth's albedo due to melting ice, and changes in atmospheric CO2 concentration during the ice ages, scientists can directly calculate the sensitivity of the climate to changes in the atmospheric CO2 concentration.

If AnthroCO2 has already delayed the next ice age, there would have to be a high climate sensitivity to CO2.

Idso's calculations for climate sensitivity are greatly at odds with the paleoclimate data; if sensitivity were as small as he proposes, the Milankovic changes in solar forcing wouldn't be enough to kickstart the climb out of an ice age, but this still presupposes AGW, that CO2 emissions will increase the temperature by some amount.

[Response: Net negative feedback (i.e. climate sensitivity less than 1 deg C) is completely inconsistent with the ice ages that you quoted above.

I'm certainly not denying that such a decease in sunspots would have an effect, but to claim it could lead to another little ice age would seem to assume fairly high climate sensitivity.

Well - documented climate changes during the history of Earth, especially the changes between the last major ice age (20,000 years ago) and the current warm period, imply that the climate sensitivity is near the 3 °C value.

This is completely unrealistic, because we've got other ways to estimate climate sensitivity, notably the temperature and albedo, dust, greenhouse gas induced forcings of the last ice age, and those independently make it quite hard for sensitivity to be less than 1.5 C or more than 4.5 C.

A barrage of comets could most certainly change climate trends and during a different time period like the last ice age could certainly have a different degree of climate sensitivity.

I agree, we'd expect climate sensitivity to be a different figure depending on the starting condition; it would be different in an ice age than now because of different albedo, and may other factors.