Limiting temperature rise by 2100 to less than 1.5°C is feasible, at least from a purely technological standpoint, according to the study published in the journal Nature Climate Change by researchers at the International Institute for Applied Systems Analysis (IIASA), the Potsdam Institute for Climate Impact Research (PIK), and others. The new study examines scenarios for the energy, economy, and environment that are consistent with limiting climate change to 1.5°C above pre-industrial levels, and compares them to scenarios for limiting climate change to 2°C.
“Actions for returning global warming to below 1.5°C by 2100 are in many ways similar to those limiting warming to below 2°C,” says IIASA researcher Joeri Rogelj, one of the lead authors of the study. “However, the more ambitious 1.5°C goal leaves no space to further delay global mitigation action and emission reductions need to scale up swiftly in the next decades.”
The authors note, however, that the economic, political, and technological requirements to meet even the 2°C target are substantial. In the run-up to climate negotiations in December 2015, such information is important for policymakers considering long-term goals and steps to achieve these goals.
Key elements: accelerated energy efficiency gains and CO2 removal
The study identifies key elements that would need to be in place in order to reach the 1.5°C target by 2100. One fundamental feature is the tight constraint on future carbon emissions.
“In 1.5°C scenarios, the remaining carbon budget for the 21st century is reduced to almost half compared to 2°C scenarios,” explains PIK researcher Gunnar Luderer, who co-led the study. “As a consequence, deeper emissions cuts are required from all sectors, and global carbon neutrality would need to be reached 10-20 years earlier than projected for 2°C scenarios.”
Faster improvements in energy efficiency also emerge as a key enabling factor for the 1.5°C target. In addition, all the scenarios show that at some point in this century, carbon emissions would have to become negative at a global scale. That means that significant amounts of CO2 would need to be actively removed from the atmosphere. This could occur through technological solutions such as bioenergy use combined with carbon capture and storage–a technology that remains untested on a large scale, increases the pressure on food supply systems and in some cases lacks social acceptance–or through efforts to grow more forests, sequestering carbon in tree trunks and branches. Afforestation, however, just like bioenergy plantations, would have to be carefully balanced against other land use requirements, most notably food production.
Overshooting the limit–and declining to 2100
In contrast to many scenarios examined in recent research, which set 2°C as the absolute limit and do not allow temperature to overshoot the target, the current set of scenarios looks at a long term goal, and what would need to happen to get temperature back down to that level by 2100.
“Basically all our 1.5°C scenarios first exceed the 1.5°C temperature threshold somewhere in mid-century,” explains Rogelj, “before declining to 2100 and beyond as more and more carbon dioxide is actively removed from the atmosphere by specialized technologies”.
The recent IPCC fifth assessment report did not describe in detail the critical needs for how to limit warming to below 1.5°C as the scenarios available to them did not allow for an in-depth analysis. Yet over 100 countries worldwide–over half of the countries in the United Nations Framework Convention on Climate Change (UNFCCC), including the Alliance of Small Island States (AOSIS) and the Least-Developed Countries (LDCs)–have declared their support for a 1.5°C target on climate change. The target itself is also up for debate at the upcoming climate negotiations. This new study fills this gap.
The authors make clear that an increase of international efforts to curb greenhouse gases is imperative to keep the 1.5°C target achievable.
“The 1.5°C target leaves very little leeway,” says Luderer. “Any imperfections – be it a further delay of meaningful policy action, or a failure to achieve negative emissions at large scale – will make the 1.5°C target unattainable during this century.”
What do you mean by “scenario?”
Scenarios, like the ones described in this study, are not predictions or forecast, but rather, stories about potential ways that the future might develop, with specific quantitative elements and details about how sectors such as the economy, climate, and energy sector interact. By looking at scenarios, researchers look for insight into the paths and circumstances that might lead us to specific objectives.
###
Reference: Rogelj J, Luderer G, Pietzcker RC, Kriegler E, Schaeffer M, Krey V, Riahi K. (2015). Energy system transformations for limiting end-of-century warming to below 1.5°C. Nature Climate Change. 21 May 2015. DOI: 10.1038/NCLIMATE2572
This is a joint press release from the International Institute for Applied Systems Analysis (IIASA) and the Potsdam Institute for Climate Impacts Research (PIK).
These people must be completely insane. It’s King Canute all over again – except that it’s costing us billions of $, £ etc. Oh, except also that the tide is not coming up the beach in the first place.
Utter, delusional nonsense.
They.Are.Mad.
Technically, we won’t have to do anything if the current trend continues.
What is the climate sensitivity they used for this theoretical exercise which above all doesn’t take into account any natural variability? Is the assumed climate sensitivity supported by observational evidence?
Our betters have decided we’re going to spend $93,100,000,000,000 by 2030 on “climate finance”:
“Over the next 15 years, the global economy will require an estimated $89 trillion in infrastructure investments across cities, energy, and land-use systems, and $4.1 trillion in incremental investment for the low-carbon transition to keep within the internationally agreed limit of a 2 degree Celsius temperature rise.”
http://www.worldbank.org/en/news/feature/2015/04/18/raising-trillions-for-climate-finance
So based on the unproven connection between rising global temperature (now only rising in the falsified surface records) and human emissions of CO2 they urge us to wreck our economies? How much more of this taxpayer funded drivel will we have to endure in the run up to Paris?
Isn’t the answer: Absolutely nothing.
It only recently dawned on me that all the talk of limiting temperature rises “to 2C by the end century”, is not rises above present temperatures but above 1850 levels (pre industrial). So this new figure of 1.5C actually means 0.7C warmer than today and the scare campaign of 2C is actually 1.2C higher temperatures than today. Not so scary at all really. I suppose it’s all in the marketing.
If climate sensitivity is just a little above 1 C, the “2C target” may be reached without any effort at all, so introducing a 1.5C target into the discussion is probably just a hedging strategy.
“what do we mean by”Scenario””
A lot of gobledy hook by the sound of it.
“In addition, all the scenarios show that at some point in this century, carbon emissions would have to become negative at a global scale”.
And still CO2 will be emitted and as naturally required. No policy available to ever control that.
We will either fry or freeze…in between will be a bit of weather.
“Limiting temperature rise by 2100 to less than 1.5°C is feasible, at least from a purely technological standpoint, according to the study published in the journal Nature Climate Change by researchers at the International Institute for Applied Systems Analysis (IIASA), the Potsdam Institute for Climate Impact Research (PIK), and others.”
And if CO2 does not do what they think it does? What if the real atmospheric greenhouse effect is instead “entirely explainable on the basis of atmospheric mass/gravity/pressure/heat capacity/adiabatic lapse rate, and the “ocean greenhouse effect” explainable on the basis of the ~0.76 – 0.89 far-IR emissivity of the oceans, which “traps” heat from solar radiation in the oceans.”? What if reducing CO2 emissions mainly hurts plant life and does little else? We have spent over 30 years now assuming the Hansen – Arrhenius – Sagan theory of CO2 and back radiation is correct. What if it is wrong?
What if climate sensitivity to CO2 is zero?
[snip – your repeated violations of site policy are going to earn you a permanent ban if it continues – stick to discussing science, not hurling smears – mod]
With the Solar output dropping, the Earth’s temperature could drop by 2C. Are we talking about limiting the temperature rise to -2.5C [2100] or -0.5C from today temperatures. They make predictions; so can I.
Given that there is genuine doubt about the sensitivity of global average temperature to CO2, how doe this article have any credibility? That is only one question of several that poses the same question.
Global warming is a sure thing. North Korea and Iran Nukes.
I think we should attempt to change the Earth’s orbit around the sun.
“Actions for returning global warming to below 1.5°C by 2100 are in many ways similar to those limiting warming to below 2°C,”
Some of the ways they are similar: 1) Completely arbitrary 2) Based on unfounded science 3) Defy all laws of economics 4) Require brutal dictatorships to enforce
What they are calling for in terms of global emission reduction is in the fig here:
http://2.bp.blogspot.com/-DC4t1sqx7sg/VV3gZK1-K7I/AAAAAAAAEtY/oxIIOBLB5S8/s1600/20150521-emission-scenarios.png
No mention that I can see of the China problem, and without resolving that question the probability of achieving zero effective emission by 2070 must be very low.
So, have the Chinese agreed? Thought not.
We have to wonder what world these people live in. Even the Phil Jones adjusted dataset, Hadcrut4, shows no warming this century.
http://s10.postimg.org/64lz3lyu1/HADCRUT4_from_2000.png
That is in spite of CO2 emissions having increased by over 35% and CO2 levels being at a record high.
All recent papers on Climate Sensitivity now estimate it to be below 2 degrees. In its latest report the IPCC couldn’t actually bring itself to acknowledge this directly and so, instead, it said
So what do these people think they are doing? No action is required to limit temperature increase to 1.5 degrees, it is not going to be exceeded anyway (according to the settled science).
Any estimates on cost are as empty as the entire global warming farce. We can’t know what it might cost because we have no clue at all what is needed to achieve that goal and, moreover, we don’t even know if there is anything we can do to even come close.
What we do know very well is that climate scientists are among the worst scientists in the history of science. Best guesses do not equate to knowledge or understanding, yet that is all they have. This can’t be fixed because they don’t believe any of this. The true climate deniers are those who believe they’re doing good work. The reality is they can’t do good work because they don’t understand their subject. This is evident in the body of their work. Any solution they come up with for any climate problems they perceive should be considered dangerous voodoo science until they get at least one GCM to work. They can’t be taken seriously until every GCM works.
“In 1.5°C scenarios…”
Thanks, read enuff.
What would it take to limit temperature to a rise of 1.5c? Since no one truly understands all aspects of the natural variability of the climate, the only way we could know what it would take is by Divine intervention, though it is possible that Satan knows as well. One thing is certain, since we have no true understanding of the climate, they can write a “SimCity” style program to simulate it, but there is no where near enough knowledge to model it, thus there is no way of knowing if there is ANYTHING we could do to limit the rise of temperature to 1.5c this century – or, for that matter the fall of 1.5c.
There is first of all not going to be any further warming going forward from this point in time and even if there should be there is nothing that we would be able to do to stop it.