Introduction

Question 1

At the twenty-first Conference of the Parties (COP21), 195 nations

Answer 1

committed to “holding the increase in the global average temperature to well below 2 °C above preindustrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change

Question 2

Describe graph

Answer 2

*

Question 3

Our assessment begins with decomposing the term adequacy into three crucial components, namely

Answer 3

necessity, feasibility, simplicity

Question 4

necessity

Answer 4

A straightforward interpretation then emerges: “GHG emissions that would modify the character of the climate system in a way that creates intolerable risks for humankind must be avoided.”

As a sensible conclusion, the Holocene mode of operation of the planetary environmental machinery needs to be preserved.

Today, Earth system science has come of age and can provide robust evidence for the intuitive assumption that it is not a good idea to leave the “safe operating space” of humanity6,7

. The keywords in this context are non-linearity and irreversibility. Impacts research indicates that unbridled anthropogenic climate change would be most likely to play out in a disruptive and irreparable wayy.

Question 5

feasibility

Answer 5

The Paris climate target is highly ambitious, if not aspirational. The long lifetime of CO2 in the atmosphere implies a strictly limited total carbon budget and thus forces us to reach zero emissions — if warming is to be stopped at all

This assessment concludes that the 2 °C guardrail can be respected at moderate cost under certain (not entirely unreasonable) assumptions, including the realization of ‘negative-emissions’ schemes.

However, the enormous challenges associated with massive atmospheric CO2 removal or negative emissions have been highlighted by several experts

We think that a better chance to deliver on the Paris promises can be generated by an alternative and more plausible route: in order to avoid the need to recourse to negative emissions as a lateregrets magic bullet (with questionable outcome), renewable energies and efficiency technologies could be scaled up exponentially, more rapidly than envisaged in the integrated assessment models behind the IPCC scenarios

We expect that such a ‘technical explosion’ will be matched by an ‘induced implosion’ of the incumbent industrial metabolism nourished by coal, oil and gas

Among the driving processes, investment dynamics is crucial, and this dynamic might in fact transgress its own tipping point in response to the narrative transpiring from Paris. This has often been described as the bursting of the ‘carbon bubble’

Question 6

simplicity

Answer 6

The latter dimension is often ignored, but is tremendously important for political recognition and implementation, as we shall explain. The feasibility question has been studied thoroughly not least by the IPCC in its Fifth Assessment Report2 (AR5). The preliminary conclusion is that the 2 °C line may be held with remarkably low economic cost, if only the political will can be mustered.

However, the feasibility issue is well worth revisiting in light of the Paris aspiration to limit warming to 1.5 °C. We begin, however, by reviewing the necessity of a global warming limit, guided by the latest insights from climate science.

Question 7

1.5-2 difference

Answer 7

Significant impacts of climate change are projected already for a warming of 1.5 °C above pre-industrial levels, and have been shown to rise substantially difference between 1.5 °C and 2 °C of global warming is apparent when considering long-term sea-level rise: Even holding global warming to 2 °C may lead to 2–3 metres of rise by the year 2300, still rising then at twice the rate as today, whereas a 1.5 °C scenario could see the peak sea level at a median estimate of 1.5 m above 2000

Question 8

beyond 2 degrees

Answer 8

Beyond 2 °C the course would be set for a complete deglaciation of the Northern Hemisphere, threatening the survival of many coastal cities and island nations. Global food supply would be jeopardized by novel extreme-event regimes, and major ecosystems such as coral reefs forced into extinction14. Yet, staying within the Paris target range, the overall Earth system dynamics would remain largely intact. Progressing into the third domain (D4) on the other hand, with global warming reaching 3–5 °C, would seriously harm most tipping elements. For warming levels beyond this range (spanning the fourth domain D8), the world as we know it would be bound to disappear.

Question 9

tipping points

Answer 9

These critical entities have been called tipping elements8 , since their character is closely related to certain pockets of planetary state space. This means that those elements may be destroyed, damaged or transmuted if critical threshold values (tipping points) of key environmental parameters are transgressed

Question 10

analysis

Answer 10

his becomes clear when one moves from the conventional, yet valuable, realms of analysis (“How will wheat yields vary with changes in local temperature, precipitation, insolation etc?”) to the macro-components, mega-patterns and super-ecosystems that determine how the climate system functions as a whole (“When will the Greenland Ice Sheet collapse under progressive global warming?”).

Question 11

solar wind costs

Answer 11

A recent study30 confirms that the deployment of solar and wind power capacities worldwide has increased exponentially while the costs of solar and wind power generation have fallen in a similarly non-linear fashion

Question 12

3 scenarios

Answer 12

First, there is the classical hypothesis that a strong climate agreement paves the way towards carbonpricing instruments that will be adopted by more and more nation states in the medium term. As a consequence, investors anticipating the so-induced rise in fossil business costs should make the rational choice to opt out of that business.

Second, there is a growing risk/chance that morals are going to interfere significantly with economics. The so-called divestment campaign has become a global social movement that demands leaving most of the fossil fuel resources in the ground21,22. In public, many business leaders and government officials still try to ridicule or dismiss this sentiment surge within civil society. Yet in private conversations they admit their worries that particularly institutional investors (such as pension funds or big foundations) might be ‘infected’ by the divestment virus.

Third, there is Schumpeter’s ‘creative destruction’ (According to Schumpeter, the “gale of creative destruction” describes the “process of industrial mutation that continuously revolutionizes the economic structure from within, incessantly destroying the old one, incessantly creating a new one”.)that might instigate a systemic innovation of the existing economic structures. Let us briefly elaborate on this: when studying industrial history for a better understanding of transformational processes, one encounters certain evidence for a semi-quantitative rule, known as Pareto Principle23, which states that in heterogeneous community production systems, roughly 80% of the total output is typically generated by roughly 20% of the individual units involved

Question 13

graph red and blue

Answer 13

slide 3

Question 14

what can you study connected to geese?

Answer 14

Geese are key species in Arctic
ecosystems, linking Europe with
the Arctic

Behaviour,
physiology and
population
Vegetation
Predation
Health and immune system 
Parasites
Pollution

Question 15

anomalies map

Answer 15

the map slide 15

Question 16

two criteria in arctic

Answer 16

two criteria slides

Question 17

Arctic sea ice extent graph

Answer 17

graph

Question 18

average monthly arctic sea ice extent

Answer 18

graph 2

Question 19

arctic temperatures graph

Answer 19

graph 3

Question 20

GHG graph

Answer 20

graph 4

Question 21

boreal forest

Answer 21

From a biological perspective, boreal forests are defined as forests growing in high-latitude environments where freezing temperatures occur for 6 to 8 months and in which trees are capable of reaching a minimum height of 5 m and a canopy cover of 10%.

Of all the biomes with forests, the boreal forest is projected to experience the largest temperature shift. So far, temperatures have shifted up to 1.5 degrees Celsius, and by the end of the century temperatures could increase by 11 degrees Celsius—a lot for an ecosystem that is generally below freezing.

The tree species in the boreal forest are well adapted to cool temperatures but may suffer in a warmer climate. Invasive forest pests like the Siberian moth or mountain pine beetle could also move further north and spread quickly, which could eradicate some tree species.

Despite the cool temperatures, these ecosystems rely on fire. Fire is important to regenerate tree species like aspen and lodgepole pine. But too many fires coming too often threatens tree health and species diversity. Frequent fire also threatens the permafrost—it can also lead to burning belowground, which melts the permafrost and can emit large amounts of carbon in a short time.

Some experts believe the boreal forest is already shifting from a carbon sink to a carbon source, meaning it emits more carbon than it stores. The long-term sustainability of this ecosystem will rely on management to encourage carbon storage and promote biodiversity.

Question 22

WAIS

Answer 22

The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves.

It is estimated that the volume of the Antarctic ice sheet is about 25.4 million km3 (6.1 million cu mi), and the WAIS contains just under 10% of this, or 2.2 million km3 (530,000 cu mi).[1] The weight of the ice has caused the underlying rock to sink by between 0.5 and 1 kilometre (0.31 and 0.62 miles)[2] in a process known as isostatic depression.

Under the force of its own weight, the ice sheet deforms and flows. The interior ice flows slowly over rough bedrock. In some circumstances, ice can flow faster in ice streams, separated by slow-flowing ice ridges. The inter-stream ridges are frozen to the bed while the bed beneath the ice streams consists of water-saturated sediments. Many of these sediments were deposited before the ice sheet occupied the region, when much of West Antarctica was covered by the ocean. The rapid ice-stream flow is a non-linear process still not fully understood; streams can start and stop for unclear reasons.[citation needed]

When ice reaches the coast, it either calves or continues to flow outward onto the water. The result is a large, floating ice shelf affixed to the continent.[3]

The West Antarctic ice sheet (WAIS) has warmed by more than 0.1 °C (0.18 °F)/decade in the last fifty years, and the warming is the strongest in winter and spring. Although this is partly offset by fall cooling in East Antarctica, this effect was restricted to the 1980s and 1990s. The continent-wide average surface temperature trend of Antarctica is positive and statistically significant at >0.05 °C (0.090 °F)/decade since 1957.[26] This warming of WAIS is strongest in the Antarctic Peninsula. In 2012, the temperature records for the ice sheet were reanalyzed with a conclusion that since 1958, the West Antarctic ice sheet had warmed by 2.4 °C (4.3 °F), almost double the previous estimate. Some scientists now fear that the WAIS could now collapse like the Larsen B Ice Shelf did in 2002.[27]

Data reveals these three glaciers are losing more ice than is being replaced by snowfall. According to a preliminary analysis, the difference between the mass lost and mass replaced is about 60%. The melting of these three glaciers alone is contributing an estimated 0.24 millimetres (0.0094 inches) per year to the rise in the worldwide sea level.[5] There is growing evidence that this trend is accelerating: there has been a 75% increase in Antarctic ice mass loss in the ten years 1996–2006, with glacier acceleration a primary cause.[6] As of November 2012 the total mass loss from the West Antarctic Ice Sheet is estimated at 118 ± 9 gigatonnes per year mainly from the Amundsen Sea coast.[7]

Large parts of the WAIS sit on a bed which is both below sea level and sloping downward inland.[A] This slope, and the low isostatic head, mean that the ice sheet is theoretically unstable: a small retreat could in theory destabilize the entire WAIS, leading to rapid disintegration. Current computer models do not account well for the complicated and uncertain physics necessary to simulate this process, and observations do not provide guidance, so predictions as to its rate of retreat remain uncertain. This has been known for decades.[9]

Rapley said, “Parts of the Antarctic ice sheet that rest on bedrock below sea level have begun to discharge ice fast enough to make a significant contribution to sea level rise. Understanding the reason for this change is urgent in order to be able to predict how much ice may ultimately be discharged and over what timescale. Current computer models do not include the effect of liquid water on ice sheet sliding and flow, and so provide only conservative estimates of future behaviour.”[12]

Question 23

coral reefs

Answer 23

https://oceanservice.noaa.gov/facts/coralreef-climate.html

Question 24

Amazon rainforest

Answer 24

The Amazon rainforest, covering much of northwestern Brazil and extending into Colombia, Peru and other South American countries, is the world’s largest tropical rainforest, famed for its biodiversity.

As habitat destruction trends interact with climate change, the concern is that the Amazon will be caught up in a set of “feedback loops” that could dramatically speed up the pace of forest lost and degradation and bring the Amazon Biome to a point of no return. This threshold, also referred to as a tipping point, may occur when Amazonian forests die and are progressively replaced by fireprone brush and savanna (ecological tipping point), and rainfall is inhibited on a regional scale (climatic tipping point).

Well tuned, the Amazon’s hydrological engine plays a major role in maintaining the global and regional climate.

Water released by plants into the atmosphere through evapotranspiration (evaporation and plant transpiration) and to the ocean by the rivers, influences world climate and the circulation of ocean currents. This works as a feedback mechanism, as the process also sustains the regional climate on which it depends.

One factor is the El Niño Southern Oscillation (ENSO), a climatic phenomenon which influences much of the climatic variability in Latin America. Although ENSO events are a natural occurrence, human-induced climate change is expected to increase their frequency in the future.

ENSO is associated with dry conditions in northeast Brazil, the northern Amazon, the Peruvian-Bolivian Altiplano, and Pacific coast of Central America. Meanwhile, southern Brazil and northwestern Peru have exhibited unusually wet conditions during ENSO events.

Another factor is deforestation, which in addition to removing forest cover causes a dramatic change in rainfall patterns and distribution. These findings imply that current deforestation in the Amazon has already altered the regional climate. They also support previous reports of increased shallow cloudiness over deforested areas.

Question 25

Arctic summer sea ice

Answer 25

With the onset of spring, it is time again for a check-in on sea ice age—the number of years that a parcel of ice has survived summer melt. As noted in previous posts, ice age provides a qualitative assessment of thickness, as older ice has more chances to thicken through ridging, rafting, and bottom ice growth (accretion) during winter. The coverage of the old, thick ice has a significant control on how much total ice survives the summer melt season—the first-year ice that grows thermodynamically over winter is more easily melted away during summer. That which survives through the summer melt season grows in age by one year. The extent of old ice declines through the winter when it drifts out of the Arctic through the Fram or Nares Strait. At the end of last summer, the extent of the oldest ice (greater than 4 years old) tied with 2012 for the lowest in the satellite record. This spring, we continue to see a dominance of first-year ice (Figure 4). The percentage of the greater than 4-year-old ice, which once comprised over 30 percent of the Arctic Ocean, now makes up only 3.1 percent of the ice cover.

Question 26

arctic ice sea extent

Answer 26

Average Arctic sea ice extent for April 2022 was 14.06 million square kilometers (5.43 million square miles) (Figure 1). This was 630,000 square kilometers (243,000 square miles) below the 1981 to 2010 average and ranked eleventh lowest in the 44-year satellite record. Extent declined slowly through the beginning of the month, with only 87,000 square kilometers (33,600 square miles) of ice loss between April 1 and April 10. The decline then proceeded at an average pace for this time of year through the reminder of the month. Reductions in sea ice extent during April occurred primarily in the Bering Sea and the Sea of Okhotsk. Other regions had small losses at most. The southern Barents Sea lost some ice, but the channel of open water north of Novaya Zemlya that persisted for much of the winter closed during April. Overall, the daily sea ice extent tracked just below the interdecile range (below 90 percent of past daily values) for the month.

Question 27

ENSO

Answer 27

El Niño–Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña. The Southern Oscillation is the accompanying atmospheric component, coupled with the sea temperature change: El Niño is accompanied by high air surface pressure in the tropical western Pacific and La Niña with low air surface pressure there.[1][2] The two periods last several months each and typically occur every few years with varying intensity per period.[3]

The two phases relate to the Walker circulation, which was discovered by Gilbert Walker during the early twentieth century. The Walker circulation is caused by the pressure gradient force that results from a high-pressure area over the eastern Pacific Ocean, and a low-pressure system over Indonesia. Weakening or reversal of the Walker circulation (which includes the trade winds) decreases or eliminates the upwelling of cold deep sea water, thus creating El Niño by causing the ocean surface to reach above average temperatures. An especially strong Walker circulation causes La Niña, resulting in cooler ocean temperatures due to increased upwelling.

Question 28

Sahel

Answer 28

The Sahel (/səˈhɛl/; Arabic: ساحل sāḥil [ˈsaːħil], “coast, shore”)[1] is the ecoclimatic and biogeographic realm of transition in Africa between the Sahara to the north and the Sudanian savanna to the south. Having a semi-arid climate, it stretches across the south-central latitudes of Northern Africa between the Atlantic Ocean and the Red Sea.

In the Central Sahel, climate change is causing more intense and frequent droughts, as well as floods, erratic rainfall, warming temperatures and regreening (wetter conditions have led to more vegetation). As a result, people experience more food insecurity and threats to their livelihoods.

Question 29

THC

Answer 29

Thermohaline circulation (THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes.[1][2] The adjective thermohaline derives from thermo- referring to temperature and -haline referring to salt content, factors which together determine the density of sea water. Wind-driven surface currents (such as the Gulf Stream) travel polewards from the equatorial Atlantic Ocean, cooling en route, and eventually sinking at high latitudes (forming North Atlantic Deep Water). This dense water then flows into the ocean basins. While the bulk of it upwells in the Southern Ocean, the oldest waters (with a transit time of about 1000 years)[3] upwell in the North Pacific.[4] Extensive mixing therefore takes place between the ocean basins, reducing differences between them and making the Earth’s oceans a global system. The water in these circuits transport both energy (in the form of heat) and mass (dissolved solids and gases) around the globe. As such, the state of the circulation has a large impact on the climate of the Earth.

Question 30

Arctic winter sea ice

Answer 30

Arctic sea ice reaches its minimum each September. September Arctic sea ice is now declining at a rate of 13% per decade, relative to the 1981 to 2010 average. This graph shows the annual Arctic sea ice minimum each September since 1979, derived from satellite observations.