What did the latest IPCC report on climate change actually say?

Climate protesters in Washington D.C., 2017. Image: Getty.

The world’s climate scientists have spoken: if we want to limit human-induced global warming to 1.5℃ we probably can. But it will be tough, given where we’re starting from.

That’s the conclusion of a new report by the UN’s Intergovernmental Panel on Climate Change (IPCC). The focus on 1.5℃ is the result of years of international negotiation. Starting in 1994, a central aim of the UN’s climate change efforts (the Framework Convention on Climate Change, or UNFCCC) was to stabilise greenhouse gas concentrations at a level that would “prevent dangerous anthropogenic interference with the climate system”. Much was written on what this meant, particularly the word “dangerous”.

Negative impacts of climate change occur on a continuum, and defining a point at which climate change becomes dangerous is difficult and contentious. On the other hand, climate change negotiations are difficult without some target to work towards.

Fifteen years later, the UNFCCC’s Copenhagen Accord introduced a 2℃ target, and its 2015 Paris Agreement was even more specific: it “aims to strengthen the global response to the threat of climate change... by holding the increase in... temperature to well below 2℃ above pre-industrial levels and pursuing efforts to limit the... increase to 1.5℃”.

The IPCC provides scientific advice to the UNFCCC, which makes policy, and the IPCC itself has never stated a temperature target. It does however list climate change risks using five “reasons for concern”. These include impacts such as “unique and threatened ecosystems and cultures” (such as coral reefs) and “extreme weather events”, each of which is rated on a scale from “undetectable” to “very high”. The IPCC’s most recent (2014) Fifth Assessment of the scientific evidence found that at around 1.5℃ warming there was a transition from moderate to high risk for threatened ecosystems and cultures and for extreme weather events. Thus there is consistency between the Paris and IPCC assessments.

The Paris Agreement asked the IPCC to report on the impacts of global warming of 1.5℃, and this new publication is the result. Its tone is not “we must avoid 1.5℃ warming”, as you might think from many commentators, but more “if we want to avoid 1.5℃ warming, this is what must be done”. The report contrasts the impact of 1.5℃ and 2℃ warmings, giving information on what would be gained by the extra effort needed to limit warming to 1.5℃.

As the IPCC’s reports are largely based on a critical assessment and synthesis of published scientific papers, many of its latest conclusions are unsurprising. There are many well recognised uncertainties in understanding climate change - for instance, even if we set a course aiming to hit 1.5℃ (which is mostly determined by future CO₂ emissions), we could end up hitting, say, 1℃ or 2℃ instead. The report provides uncertainty ranges in its estimates and confidence levels, based on expert judgement.


The new report tells us that human activity has already caused about 1℃ of global warming, while at the present rate of warming (0.2℃ per decade) we’ll hit 1.5℃ by about 2040. National pledges made as part of the Paris Agreement still mean we are on course for warming of about 3℃ by 2100, meaning four of the five “reasons for concern” would then be in the high to very-high risk category.

Achieving the 1.5℃ target will require anthropogenic CO₂ emissions to decline by 45 per cent by 2030 (relative to 2010). By 2050, they will need to reach “net zero” - any further CO₂ emissions due to human activity would then have to be matched by deliberate removal of CO₂ already in the atmosphere, including by planting trees. Net zero would have to occur by around 2075 to meet a 2℃ target.

Many illustrations are given for the difference between 1.5℃ and 2℃ worlds. At 1.5℃, summertime Arctic sea ice is projected to disappear once per century, compared to once per decade at 2℃; 8 per cent of plants that have been studied would lose half their climatically-suitable area, compared to 16 per cent; sea level rise would be 10cm less (with 10m fewer people impacted at today’s population levels); and while coral reefs might decline by a further 80% at 1.5℃, they could virtually disappear at 2℃.

The report identifies various routes by which emissions cuts would limit warming to 1.5℃; each makes assumptions about future changes in, for example, economic strategy, population growth and the rate at which low carbon energy is adopted. The IPCC recognises the challenges are “unprecedented in scale” but notes, for example, “the feasibility of solar energy, wind energy and electricity storage mechanisms have substantially improved over the past few years”.

The report is sensitive to the fact that changes required to meet 1.5℃ must be consistent with the UN’s wider sustainable development goals. Limiting climate change will help meet goals associated with health, clean energy, cities and oceans. But there are potential negative impacts on others (poverty, hunger, water, energy access) “if not carefully managed”.

So where next? Of course, the conclusions will be widely debated at many levels, but eyes will be on the UNFCCC’s response at its next meeting, in Katowice, Poland, in early December.

The Conversation

Keith Shine, Regius Professor of Meteorology and Climate Science, University of Reading.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

 
 
 
 

How US planners experimented with “the iron hand of power” over colonial Manila

Manila in ruins, 1945. Image: Wikimedia Commons.

In 1904, Manila must have appeared to its new overlords a despairing prospect. Racked with poverty and disease, it was still recovering from years of war, epidemic and a fire that had left 8,000 homeless.

For architect Daniel Burnham, it was an opportunity to put to work the radical ideas he had dreamed of in America.

He was among those asking how America’s unprecedented wealth at the turn of the century could be reconciled with the lives of the country’s poorest. Like many, he admired the ideas of harmonised city-planning articulated in Edward Bellamy’s bestselling science-fiction Looking Backward (1888).

At the 1893 World’s Columbian Exposition in Chicago, Burnham constructed the “White City”. Built across 686 acres of parkland, boulevards, gardens and neoclassical structures rendered a spray-painted plaster vision of the future – all laid out to one comprehensive plan.

It was impressive – but implementing grand designs where people actually lived meant laborious negotiations with citizens, businessmen and politicians.

Instead, opportunity lay in America’s new overseas territories. As Daniel Immerwahr describes in How to Hide an Empire: A Short History of the Greater United States, “They functioned as laboratories, spaces for bold experimentation where ideas could be tried with practically no resistance, oversight, or consequences.”

An architect’s dream

The US had gone to war with Spain in 1898, taking advantage of an empire-wide insurrection. It ended up controlling the entire Philippines, along with Guam and Puerto Rico.

As a “territory”, the Philippines existed outside the protections of the constitution. Congress could impose any law, proclaimed the attorney general in 1901, “without asking the consent of the inhabitants, even against their consent and against their protest, as it has frequently done.”

Which is how Burnham, upon invitation by the Philippine’s new rulers, came to wield what the Architectural Record called “the iron hand of power” over Manila.

 Burnham’s plan for Manila. Click to expand.

Where Burnham’s Chicago plan was complex, took years and entailed collaboration with hundreds of citizens, Burnham spent six months on the Manila plan, and just six weeks in the Philippines. And with no voters to persuade, there seemed little reason to register Filipino input in his designs.

In 1905 Burnham submitted his Report on Improvement of Manila. It described filling the toxic moat of the Spanish fortress Intramuros and developing a rectangular street system modelled on Washington D.C., with diagonal arteries which even Chicago lacked.


Central to his plan was the city’s beautification through monumental buildings, waterfront improvements, and parks – “wholesome resorts” to “give proper means of recreation to every quarter of the city”

Burnham charged William E. Parsons as the omnipotent “Consultant Architect” to interpret his plan, who relished its authority over all public building as an “architect’s dream”. When concerned with the extent of his purview, he also chose to standardise a number of public buildings.

“I doubt if this method would bear fruit in our own city improvement plans, in which everything depends on slow moving legislative bodies,” reported the Architectural Record’s correspondent.

Despite Burnham’s colonial sentiments his biographer concluded his plan was “remarkable in its simplicity and its cognizance of Philippine conditions and traditions.”

His plans did not shy from asserting the colonial government’s authority, however. The Luneta, a favourite park, was to become the nuclei of government. The city’s avenues would converge there, for “every section of the Capitol City should look with deference toward the symbol of the Nation’s power.”

Unusual monumental possibilities

Burnham also worked on a summer palace for US administrators at Baguio, 150 miles north in the mountains. On land inhabited by Igorot people, Burnham saw an opening “to formulate my plans untrammelled by any but natural conditions”.

Baguio’s “unusual monumental possibilities” were facilitated by a road whose construction employed thousands, risking death from disease and falling off cliffs. Civic buildings would “dominate everything in sight” and a golf course would rival those of Scotland.

“Stingy towards the people and lavish towards itself,” griped La Vanguardia, the government “has no scruples nor remorse about wasting money which is not its own.”

As enthusiasm for US empire soured in the States, local power was relinquished to Filipinos. Parsons resigned in protest in 1914. He was replaced by Manila-born Juan Arellano, whose rebuke to imperialists was the mighty, neoclassical Legislative Building which hosted the elected Philippine Legislature. Arellano upheld Burnham’s plan, producing a beautified city bearing resemblance to Burnham’s White City.

But the Legislative Building, along with Burnham’s great edifices and almost everything else in Manila, was levelled as US troops recaptured it in 1945, this time ousting the Japanese in a brutal battle. “Block after bloody block was slowly mashed into an unrecognizable pulp”, recorded the 37th Infantry Division as they exercised their own “iron hand” over Manila.

American artillery had transformed Manila into ruins. “It was by far the most destructive event ever to take place on US soil,” writes Immerwahr, even if few soldiers realised they were liberating US nationals at the time. Burnham’s expansive vision was lost in the debris, and though some buildings were rebuilt a majority were replaced. Today, Manila’s pre-war architecture is remembered with fondness and nostalgia.