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Tampilkan postingan dengan label IPCC. Tampilkan semua postingan

IPCC seeks to downplay global warming

The graph below shows global warming for a 30-year period centered on January 2018, using NASA 2003 to January 2018 LOTI anomalies from 1951-1980, adjusted by 0.59°C to cater for the rise from preindustrial to 1951-1980, and with a polynomial trend added.


From: ECMWF Nino Plumes
Above graph shows that the 1.5°C guardrail, set at the Paris Agreement, was crossed in 2016 and that a 10°C (18°F) warming could eventuate within a decade or so.

The variations in above temperature data are strongly influenced by El Niño/La Niña. We currently are in a La Niña period, during which surface temperatures are suppressed, whereas surface temperatures in 2016 were much above the trendline, due to El Niño.

The ECMWF forecast from 1 February 2018 on the right indicates that we're heading for another El Niño, i.e. surface temperatures will be rising strongly over the coming months.

The IPCC seeks to downplay the amount of global warming that has already occurred and that looks set to eventuate over the next decade or so. A leaked draft of the IPCC 'Special Report on 1.5°C above pre-industrial' (First Order Draft of SR1.5 SPM) estimates that the global mean temperature reached approximately 1°C above pre-industrial levels around 2017/2018. The IPCC appears to have arrived at this estimate using an extrapolation or near term predictions of future warming so that the level of anthropogenic warming is reported for a 30 year period centered on today.

This 1°C IPCC estimate looks quite incredible when calculating the temperature rise using NASA's data for the two most recent years for which data are available (2016/2017), which shows a warming of 0.95°C when using a baseline of 1951-1980 and a warming of 1.23°C when using a baseline of 1890-1910.


Indeed, the temperature rise differs depending on which baseline is used, and when using preindustrial as a baseline, i.e. the baseline agreed to at the Paris Agreement, indications are that temperatures have already risen by more than 1.5°C, as also discussed in an earlier post.

Furthermore, when using a 30-year period centered on January 2018, the current temperature will have to be calculated over the past 15 years and estimated for the next 15 years, i.e. up to the year 2033.

To arrive at a 1°C rise for the 30-year period, the IPCC must somehow assume that temperatures will magically fall dramatically over the next 15 years, whereas indications are that temperatures will instead rise dramatically over the next decade or so.

The image on the right shows that 10°C (18°F) warming from preindustrial could eventuate within one decade when taking into full account the warming that could result from the elements depicted in the stacked bar. Each of these warming elements is discussed in more detail at the extinction page.

The image below shows the rise from 1750 to 2030, in surface temperatures (land+ocean), rather than in anomalies.


The situation is dire and calls for comprehensive and effective action, as described in the Climate Plan.


It's time to 'Do the math' again

By David Spratt

Have we gone mad? A new report released today explains why contemporary climate change policy-making should be characterised as increasingly delusional.

As the deadline approaches for submissions to the Australian government's climate targets process, there is a flurry of submissions and reports from advocacy groups and the Climate Change Authority.

Most of these reports are based on the twin propositions that two degrees Celsius (2°C) of global warming is an appropriate policy target, and that there is a significant carbon budget and an amount of "burnable carbon" for this target, and hence a scientifically-based escalating ladder of emission-reduction targets stretching to mid-century and beyond.

A survey of the relevant scientific literature by David Spratt, "Recount: It's time to 'Do the math' again", published today by Breakthrough concludes that the evidence does not support either of these propositions.

The catastrophic and irreversible consequences of 2°C of warming demand a strong risk-management approach, with a low rate of failure. We should not take risks with the climate that we would not take with civil infrastructure.

There is no carbon budget available if 2°C is considered a cap or upper boundary as per the Copenhagen Accord, rather than a hit-or-miss target which can be significantly exceeded; or if a low risk of exceeding 2°C is required; or if positive feedbacks such as permafrost and other carbon store losses are taken into account.

Effective policy making can only be based on recognising that climate change is already dangerous, and we have no carbon budget left to divide up. Big tipping-point events irreversible on human time scales such as in West Antarctica and large-scale positive feedbacks are already occurring at less than 1°C of warming. It is clear that 2°C of climate warming is not a safe cap.

In reality, 2°C is the boundary between dangerous and very dangerous climate change and 1°C warmer than human civilisation has ever experienced.

In the lead up to the forthcoming Paris talks, policy makers through their willful neglect of the evidence are in effect normalising a 2.5–3°C global warming target.

This evidence in "Recount: It's time to 'Do the math' again" demonstrates that action is necessary at a faster pace than most policy makers conceive is possible.



Related

- It's time to 'Do the math' again
http://www.climatecodered.org/2015/04/its-time-to-do-math-again.html

- RECOUNT - It's time to 'Do the math' again
http://media.wix.com/ugd/148cb0_938b5512abfa4d4e965ec8cc292893f7.pdf

- Two degrees of warming closer than you may think
http://arctic-news.blogspot.com/2015/02/two-degrees-of-warming-closer-than-you-may-think.html

- The real budgetary emergency and the myth of "burnable carbon"
http://arctic-news.blogspot.com/2014/05/the-real-budgetary-emergency-and-the-myth-of-burnable-carbon.html

It's time to 'Do the math' again | by David Spratt http://arctic-news.blogspot.com/2015/04/its-time-to-do-math-again.html

Posted by Sam Carana on Thursday, April 23, 2015