Tag Archives: temperature stabilisation

Climate action: a doddle or deep adaptation?

Again, this post started as an edition of Climate clippings.

Where I ended up after a series of happenings as described below, is concluding that we need a paradigm shift in our climate change aspirations. Instead of trying to limit warming to a point where we can avoid dangerous climate change, we need to recognize that we’ve already gone too far, that the climate is already dangerous, so we should aim to ratchet down GHG concentrations in the atmosphere to attain a safe climate.

1. Germans look to 7.4 trillion tons of fake snow to save the West Antarctic Ice Sheet

Continue reading Climate action: a doddle or deep adaptation?

Saudis throw a spanner

Climate science was buried at a meeting in Bonn. Meanwhile diplomats planted trees to symbolise their intention to combat desertification (Photo: UNFCCC)

At a mid-year meeting of UNFCCC in Bonn this year in June a small group of countries led by Saudi Arabia have put the kybosh on any formal consideration of the IPCC Special Report on 1.5°C in the UNFCCC forum. Continue reading Saudis throw a spanner

IPCC on 1.5°C: the target is wrong, but we have a strong wake-up call

The target should not be 1.5°C; rather we should aim for a safe climate. James Hansen told us in 2007 that to achieve a safe climate we need to bring GHG concentrations down to 350 ppm as soon as possible. That’s CO2 equivalent, not CO2. Current CO2e is not often quoted, but would be around 500 ppm on the basis that CO2 is about 80% of total GHGs. Also we need to focus on what we are doing to the planet over centuries and millennia, not just the next 50 to 100 years.

However, the IPCC team putting the report together were not asked what the goal should be. They were asked to build a scenario for achieving the 1.5°C warming limit specified as desirable in the Paris Agreement of 2015, and to look at the impacts of a 1.5°C world as against a 2°C world. Two Degrees came out of Europe in the 1990s, achieved a general currency, then became the official goal of at the Conference of Parties of the UNFCCC in Cancun in 2010. At that time there was a move mainly by many of the island states vulnerable it inundation for a more ambitious target. Essentially the whole group at Paris agreed to try.

However, while two degrees was commonly seen as a guardrail for a safe climate even by many scientist, it was never a scientifically derived goal for a safe climate.

The IPCC Special Report on 1.5°C is important because it shows that the path to 1.5°C has a high degree of difficulty and has implications which to most will not be acceptable. It’s importance is in changing the discourse, from being seen as an achievable safe guardrail to 1.5°C as difficult to achieve and far from safe. Continue reading IPCC on 1.5°C: the target is wrong, but we have a strong wake-up call

Science shows the need for urgent climate action

In August last year in Climate clippings 181 (Item 5) I linked to a report by Climate Analytics examining the impacts on Australia of limiting global temperature rise to 1.5°C and 2°C.

For me the crux of the report is this, from a discussion piece at The Conversation:

    The report predicts that half of the world’s identified tipping points – such as the collapse of polar ice sheets and the drying out of the Amazon rainforest – would be crossed under 2C warming, compared with 20% of them at 1.5℃.

If we go to 2℃, we will have a very different climate and there is a good chance we won’t be able to stabilise there. The bad news is that if we just carry on we’ll reach 1.5C by 2024, and 2C by 2036. Continue reading Science shows the need for urgent climate action

Hansen’s new temperature graph heads north

James Hansen and Makiko Sato have just released a new temperature graph, which highlights the underlying trend, and is more than a little alarming:

hansen_temperature_cropped_600

See also his blog post that looks at the implications and what we need to do. Continue reading Hansen’s new temperature graph heads north

Saving the planet

At the Paris climate conference a surprise result was for the world to aim to hold “the increase in … temperature to well below 2°C … and to pursue efforts to limit the temperature increase to 1.5°C”.

Fred Pearce in the New Scientist now takes a look at what some are saying needs to be done. Continue reading Saving the planet

Climate clippings 153

1. July hottest ever

Not just the hottest July, we’ve just had the hottest single month since records began in 1880. It’s also been the hottest first seven months of any year, so we are heading into new territory. Continue reading Climate clippings 153

Is 1.5°C attainable?

With increasing appreciation that limiting global temperature rises to 2°C amounts to folly, is 1.5°C attainable? Is 2°C the best remaining scenario on offer?

For the Bonn UNFCCC climate talks in June a report was presented from 70 scientists gathered together in a process called the “structured expert dialogue”. It warned that even current levels of global warming of around 0.85°C are already intolerable in some parts of the world: Continue reading Is 1.5°C attainable?

Two degrees

Carbon Brief has compiled a series of three posts on the so-called 2°C ‘guardrail’ used in global warming discourse:

This post will pick out some of the highlights, but is not a substitute for reading the posts.

The history of two degrees

To me there have been four critical events:

  • From 1975 Yale economics professor William Nordhaus suggested that warming of more than two degrees would push the climate beyond the limits humans were familiar with.
  • In 1990 a team of researchers from the Stockholm Environment Institute (SEI) attempted to define what constituted dangerous climate change. They suggested two degrees.
  • In 1996 the European Council of environment ministers declared that “global average temperatures should not exceed 2 degrees above pre-industrial level”.
  • At the Conference of Parties of the UNFCCC in Cancun in 2010 governments committed to “hold the increase in global average temperature below 2°C above pre-industrial levels.”

Notably the SEI in 1990 was nuanced and cautious:

Based on scientific understanding at the time, SEI suggested that to avoid the worst impacts of climate change, a limit should be set at two degrees. But, the report warned, the higher the temperature rise, the bigger the risks from climate change.

“Temperature increases beyond 1.0°C may elicit rapid, unpredictable, and non-linear responses that could lead to extensive ecosystem damage,” the report said, suggesting there is nothing necessarily ‘safe’ about a two degree limit. (Emphasis added)

In their view 2°C was not a guardrail where it was safe on one side and dangerous on the other. In my view the notion of a ‘guardrail’ is majorly misleading.

Can we avoid dangerous climate change?

The distilled wisdom is that we have a historical emissions budget of 2,900 billion tonnes of carbon dioxide if we are to have a 66% chance of staying below two degrees. We’ve used up 1,900 of that budget so the remaining budget is 1000 billion tonnes. At current rates we’ll use up that budget in 21 years. Unfortunately emissions are increasing.

If emissions were to peak today they would need to start falling at 5.5% per year from tomorrow, in order to achieve a 66% chance of staying within a two degrees increase. France managed 5% per year for half a decade at the height of its 30-year shift to nuclear, during which it went from one per cent nuclear-powered to 80%. That kind of effort would be required worldwide on average for decades.

Increasingly the assumption is that we need to reach zero net emissions around 2055 to 2070 and then go net negative, using technology that has not yet been developed.

The article canvasses a number of stabilisation strategy scenarios and includes this interesting map of electricity generation change required by 2040 from the International Energy Association’s World Energy Outlook 2014:

energyoutlookmaplogo_600

The message is that the investment in renewables needs to be massive. Coal must reduce in the US, the EU and China, but could increase elsewhere, substantially so in India. Everyone will use more gas.

I would query the role of gas as a transition technology for two reasons. Firstly, I think we need to decarbonise so rapidly that gas would need to be phased out before an adequate return on investment is achieved. Secondly, I’m concerned about its true greenhouse effectiveness, because of fugitive emissions in production, transmission and usage, and because I think the greenhouse impact of methane is underestimated.

It’s no surprise that I would also query the accepted wisdom about the remaining carbon budget. A one third chance of failure is unacceptable, David Spratt points out that if we want a 90% chance of success there is no carbon budget left.

I agree with the article that we should never call “game over” in climate mitigation efforts.

See also my post The UNEP Emissions Gap Report: a failure of ambition.

What happens if we overshoot two degrees?

There is much uncertainty about the specifics, but this mega graphic gives the overall impact of four degrees as against two degrees in four aspects:

ar5globalimpacts_600

The article says that change should be seen as a continuum rather than as a precipice. I’d agree, but I think we should assume that a precipce that we can’t see is there and the chances of meeting up with it increase as the temperature increases. In short, the more warming we have the more we are likely to trigger tipping points that make the climate less stable.

I have a massive query with this statement:

Global temperature has risen 0.85 degrees Celsius since 1880, according to the latest report from the Intergovernmental Panel on Climate Change (IPCC).

We could be due another couple of tenths on top of that as past emissions take a decade or so to reach their full effect warming. Together with current and expected emissions we’re essentially already committed to about one degree of warming, scientists estimate.

The article cites one study that sees warming effects flowing through in about a decade. I suspect that only short-term feedbacks are being considered.

David Spratt’s paper Is climate change already dangerous? says:

And the IPCC (2007) Synthesis report (Table 5.1 on emission scenarios) also shows that for levels of greenhouse gases that have already been achieved (CO2 in the range of 350–400 ppm,CO2e in the range 445–490 ppm) and peaking by 2015, the likely temperature rise is in the range of 2–2.4°C.

I’ll finish with a reminder that the Swedes got it right – two degrees does not mean a safe climate.

See also my The folly of two degrees: Climate Code Red.

The folly of two degrees

Back in 2011 David Spratt took a look at where we were in relation to temperature rise and the Holocene. At 2000 we were at 0.7°C above the pre-industrial temperature. This happens to coincide with the Holocene maximum:

Holocene_thin-blue-line 600

Spratt says James Hansen warns that at 0.7°C the ice sheets start to become unstable, so in terms of sea level rise alone we are entering a danger zone. Since then the temperature has risen ~ 0.15°C.

From this point of view the 2°C guardrail looks hazardous in the extreme. Continue reading The folly of two degrees

Assessing dangerous climate change

Seventeen high-profile academics with expertise across the climate research spectrum, from atmospheric science, earth science and environmental science, to economics, global change and public health led by James Hansen, now at Columbia University’s Earth Institute, have published a paper Assessing “Dangerous Climate Change”: Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature which demands attention.

The bottom line is that “aiming for the 2°C pathway would be foolhardy” because it “would have consequences that can be described as disastrous”. The authors believe that humanity and nature, the modern world as we know it, is adapted to the Holocene climate that has existed more than 10,000 years. Departing from this climate by more than 1°C would have intrinsically harmful effects. At 2°C these effects become unacceptably severe. Moreover we enter a zone where further feedbacks, such as ice sheet response, methane release and vegetation change, are likely to push the climate towards further warming, of probably at least 3°C.

James Hansen and Pushker Kharecha have done a summary with discussion here, then there’s Joe Romm at Climate Progress, Tim Radford at Climate Code Red, Damian Pattinson, Editorial Director, PLOS ONE, at Huff Post and John Rennie with links to further material at PLOS Blogs. My partial summary is below. Continue reading Assessing dangerous climate change