Tag: projections
“We need drastic, radical emissions reductions, and on top of that we need some CDR,” said Glen Peters, research director at the Centre for International Climate Research.
There are basically two ways to extract CO₂ from air.
One is to boost nature’s capacity to absorb and stockpile carbon. Healing degraded forests, restoring mangroves, industrial-scale tree planting, boosting carbon uptake in rocks or the ocean—all fall under the hotly debated category of “nature-based solutions”.
The second way—called direct air capture—uses chemical processes to strip out CO₂, then recycles it for industrial use or locks it away in porous rock formations, unused coal beds or saline aquifers.
A variation known as bioenergy with carbon capture and storage, or BECCS, combines elements from both approaches.
CO₂ removal will be required for two reasons. Firstly, even if the world begins drawing down carbon pollution by 3, 4 or 5% per year—and that is a very big “if”—some sectors like cement and steel production, long-haul aviation and agriculture are expected to maintain emission levels for decades.
Secondly, the August report from the UN’s Intergovernmental Panel on Climate Change (IPCC) makes it alarmingly clear that the 1.5˚C threshold will be breached in the coming decades no matter how aggressively greenhouse gases are drawn down. CO₂ lingers in the atmosphere for centuries, which means that the only way to bring warming back to 1.5˚C by 2100, is to suck some of it out of the air.
BECCS was pencilled into IPCC climate models more than a decade ago as the theoretically cheapest form of negative emissions, but has barely developed since.
A peer-reviewed proposal in 2019 to draw down excess CO₂ by planting a trillion trees sparked huge excitement in the media and among gas and oil companies that have made afforestation offsets a central pillar of their attempts to align with Paris treaty goals. But the idea was sharply criticised by experts, who pointed out that it would require converting twice the area of India into mono-culture tree farms.
Also, planting trees to soak up CO₂ is fine until the forests burn down in climate-enhanced wildfires.
Among all the carbon dioxide removal methods, direct air capture (DAC) is among the least developed but the most talked about. Assuming investment of a trillion dollars a year starting now, DAC knocked off some two billion tonnes of CO₂ annually from global emissions by 2050 in models. But only when coupled with the most ambitious carbon-cutting scenario laid out by the IPCC was that enough to bring temperatures back down—after rising to 2˚C—to around 1.7˚C by 2100.
For David King, chair of the Climate Crisis Advisory Group, “Net-zero by 2050 is no longer enough. We must revise global targets beyond net zero and commit to net negative strategies”.
Today’s emission reduction pledges cover less than 20% of the gap that needs to be closed by 2030 to keep a 1.5 °C path within reach.
For all the advances being made by renewables and electric mobility, 2021 is seeing a large rebound in coal and oil use. Largely for this reason, it is also seeing the second-largest annual increase in CO2 emissions in history.
Public spending on sustainable energy in economic recovery packages has only mobilised around one-third of the investment required to jolt the energy system onto a new set of rails, with the largest shortfall in developing economies that continue to face a pressing public health crisis.
National net zero emission targets could, if fully implemented, reduce best estimates of projected global average temperature increase to 2.0–2.4 °C by 2100, bringing the Paris Agreement temperature goal within reach.
A total of 131 countries are discussing, have announced or have adopted net zero targets, covering 72% of global emissions.
Currently implemented policies will increase warming by 2.9–3.2 °C, and pledges submitted to the Paris Agreement will increase warming by 2.4–2.9 °C.
Earth’s temperature is projected to hit 1.5˚C or 1.6˚C around 2030 in all five scenarios—a full decade earlier than a similar prediction the IPCC made less than three years ago.
The news gets worse.
By mid-century, the 1.5C threshold has been breached across the board—by a tenth of a degree along the most ambitious pathway, and by nearly a full degree at the opposite extreme.
The glimmer of hope for 1.5˚C is that by century’s end Earth’s surface will have cooled a notch to 1.4˚C under the most optimistic “if-we-do-everything-right” storyline.
A brief overshoot does not mean the target has been missed, scientists caution.
But long-term trajectories do not look promising in the other four scenarios.
Temperature increases by 2090 forecast range from a hugely challenging 1.8˚C to a catastrophic 4.4˚C.
“There is definitely a difference of opinion among scientists about whether the 1.5C target is reachable,” Tim Lenton, director of the Global Systems Institute at the University of Exeter and an authority on climate tipping points, told AFP.
Some experts who think 1.5C is mission impossible simply avoid the subject to avoid casting a pall over efforts to ramp up climate action, he added. “They don’t discuss it.”
“We find that there is a substantial mismatch between likely warming rates and research coverage. 1.5 °C and 2 °C scenarios are substantially overrepresented. More likely higher end warming scenarios of 3 °C and above, despite potential catastrophic impacts, are severely neglected.“
Chair of CCAG, Sir David King said: “I believe we have five years left to get on top of this global problem. We began talking seriously about climate change in 1992, yet we are now in a worse position with growing emissions and rising risks—watching greenhouse gases increase year after year.”
“But we’ve also let this problem get to the point where rapid emission reductions alone won’t be enough—we also need to develop ways to remove large amounts of carbon dioxide from the atmosphere and to preserve critical parts of the Earth system while we still can.”
Species extinction, more widespread disease, unliveable heat, ecosystem collapse, cities menaced by rising seas—these and other devastating climate impacts are accelerating and bound to become painfully obvious before a child born today turns 30.
On current trends, we’re heading for 3˚C at best.
Prolonged warming even beyond 1.5 degrees Celsius could produce “progressively serious, centuries’ long and, in some cases, irreversible consequences” the report notes.
The world must face up to this reality and prepare for the onslaught — a second major takeaway of the report.
“Current levels of adaptation will be inadequate to respond to future climate risks”
Mid-century projections—even under an optimistic scenario of 2˚C of warming—make this an understatement.
Tens of millions more people are likely to face chronic hunger by 2050, and 130 million more could experience extreme poverty within a decade if inequality is allowed to deepen.
In 2050, coastal cities on the “frontline” of the climate crisis will see hundreds of millions of people at risk from floods and increasingly frequent storm surges made more deadly by rising seas.
Some 350 million more people living in urban areas will be exposed to water scarcity from severe droughts at 1.5˚C of warming — 410 million at 2˚C.
That extra half-a-degree will also mean 420 million more people exposed to extreme and potentially lethal heatwaves.
Thirdly, the report outlines the danger of compound and cascading impacts, along with point-of-no-return thresholds in the climate system known as tipping points, which scientists have barely begun to measure and understand.
Recent research has shown that warming of 2˚C could push the melting of ice sheets atop Greenland and the West Antarctic—with enough frozen water to lift oceans 13 metres (43 feet)—past a point of no return.
Other tipping points could see the Amazon basin morph from tropical forest to savannah, and billions of tonnes of carbon leech from Siberia’s permafrost, fuelling further warming.
“But simply swapping a gas guzzler for a Tesla or planting billions of trees to offset business-as-usual isn’t going to cut it“
“We need transformational change operating on processes and behaviours at all levels: individual, communities, business, institutions and governments”
“We must redefine our way of life and consumption.”
“There is no longer any realistic chance for an orderly transition.”
Year 2100, the nightmare scenario:
→ Massive frequent wildfires
→ Dead coral reefs
→ Frequent prolonged droughts
→ Increased air pollution
→ Ice-free Arctic summers
→ Rapid sea level rise
→ Abandoned small island nations
→ Billions of people suffering water stress
→ Stronger cyclones
→ More frequent mega-cyclones causing devastation
→ More intense & unpredictable monsoons affecting 3 billion people
→ Half of the land devoted to agriculture in the past now unusable
→ Plummeting crop yields
→ Collapsed fish stocks
→ Deaths from tuberculosis, malaria, cholera, diarrhoea and respiratory illnesses at their highest levels in human history.