Editing IPCC:AR6/SR15/Chapter-3 (section)

==== 3.5.4.10 Fynbos and shrub biomes ====

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The Fynbos and succulent Karoo biomes of South Africa are threatened systems that were assessed in AR5. Similar shrublands exist in the semi-arid regions of other continents, with the Sonora-Mojave creosotebush-white bursage desert scrub ecosystem in the USA being a prime example. Impacts accrue across these systems with greater warming, with impacts at 2°C ''likely'' to be greater than those at 1.5°C ( ''medium confidence'' ). Under 2°C of global warming, regional warming in drylands is projected to be 3.2°C–4°C, and under 1.5°C of global warming, mean warming in drylands is projected to still be about 3°C. The Fynbos biome in southwestern South Africa is vulnerable to the increasing impact of fires under increasing temperatures and drier winters ( ''high confidence'' ). The Fynbos biome is projected to lose about 20%, 45% and 80% of its current suitable climate area relative to its present-day area under 1°C, 2°C and 3°C of warming, respectively (Engelbrecht and Engelbrecht, 2016) <sup>[[#fn:r1224|1224]]</sup> , demonstrating the value of climate change mitigation in protecting this rich centre of biodiversity.

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'''Table 3.6'''

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'''Emergence and intensity of climate change hotspots under different degrees of global warming.'''

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{| class="wikitable"
|-
! Region and/or Phenomenon
! Warming of 1.5°C or less
! Warming of 1.5°C–2°C
! Warming of 2°C–3°C
|-
| Arctic sea ice
| Arctic summer sea ice is ''likely'' to be maintained
Habitat losses for organisms such as polar bears,<br />
whales, seals and sea birds

Benefits for Arctic fisheries

| The risk of an ice-free Arctic in summer is about 50% or higher
Habitat losses for organisms such as polar bears, whales,seals and sea birds may be critical if summers are ice free

Benefits for Arctic fisheries

| The Arctic is ''very likely'' to be ice free in summer
Critical habitat losses for organisms such as polar bears, whales, seals and sea birds

Benefits for Arctic fisheries

|-
| Arctic land regions
| Cold extremes warm by a factor of 2–3, reaching up to 4.5°C ( ''high confidence'' )
Biome shifts in the tundra and permafrost deterioration are ''likely''

| Cold extremes warm by as much as 8°C ( ''high confidence'' )
Larger intrusions of trees and shrubs in the tundra than under 1.5°C of warming are ''likely'' ; larger but constrained losses in permafrost are ''likely''

| Drastic regional warming is ''very likely''
A collapse in permafrost may occur ( ''low confidence'' ); a drastic biome shift from tundra to boreal forest is possible ( ''low confidence'' )

|-
| Alpine regions
| Severe shifts in biomes are ''likely''
| Even more severe shifts are ''likely''
| Critical losses in alpine habitats are ''likely''
|-
| Southeast Asia
| Risks for increased flooding related to sea level rise
Increases in heavy precipitation events

Significant risks of crop yield reductions are avoided

| Higher risks of increased flooding related to sea level rise ( ''medium confidence'' )
Stronger increases in heavy precipitation events ( ''medium confidence'' )

One-third decline in per capita crop production ( ''medium confidence'' )

| Substantial increases in risks related to flooding from sea level rise
Substantial increase in heavy precipitation and high-flow events

Substantial reductions in crop yield

|-
| Mediterranean
| Increase in probability of extreme drought ( ''medium confidence'' )
''Medium confidence'' in reduction in runoff of about 9% ( ''likely'' range 4.5–15.5%)

Risk of water deficit ( ''medium confidence'' )

| Robust increase in probability of extreme drought ( ''medium confidence'' )
''Medium confidence'' in further reductions (about 17%) in runoff ( ''likely'' range 8–28%)

Higher risks of water deficit ( ''medium confidence'' )

| Robust and large increases in extreme drought. Substantial reductions in precipitation and in runoff ( ''medium confidence'' )
Very high risks of water deficit ( ''medium confidence'' )

|-
| West Africa and the Sahel
| Increases in the number of hot nights and longer and more frequent heatwaves are ''likely''
Reduced maize and sorghum production is ''likely'' , with area suitable for maize production reduced by as much as 40%

Increased risks of undernutrition

| Further increases in number of hot nights and longer and more frequent heatwaves are ''likely''
Negative impacts on maize and sorghum production ''likely'' larger than at 1.5°C; ''medium confidence'' that vulnerabilities to food security in the African Sahel will be higher at 2°C compared to 1.5°C

Higher risks of undernutrition

| Substantial increases in the number of hot nights and heatwave duration and frequency ( ''very likely'' )
Negative impacts on crop yield may result in major regional food insecurities ( ''medium confidence'' )

High risks of undernutrition

|-
| Southern Africa
| Reductions in water availability ( ''medium confidence'' )
Increases in number of hot nights and longer and more frequent heatwaves ( ''high confidence'' )

High risks of increased mortality from heatwaves

High risk of undernutrition in communities dependent on dryland agriculture and livestock

| Larger reductions in rainfall and water availability ( ''medium confidence'' )
Further increases in number of hot nights and longer and more frequent heatwaves ( ''high confidence'' ), associated increases in risks of increased mortality from heatwaves compared to 1.5°C warming ( ''high confidence'' )

Higher risks of undernutrition in communities dependent on dryland agriculture and livestock

| Large reductions in rainfall and water availability ( ''medium confidence'' )
Drastic increases in the number of hot nights, hot days and heatwave duration and frequency to impact substantially on agriculture, livestock and human health and mortality ( ''high confidence'' )

Very high risks of undernutrition in communities dependent on dryland agriculture and livestock

|-
| Tropics
| Increases in the number of hot days and hot nights as well as longer and more frequent heatwaves ( ''high confidence'' )
Risks to tropical crop yields in West Africa, Southeast Asia and Central and South America are significantly less than under 2°C of warming

| The largest increase in hot days under 2°C compared to 1.5°C is projected for the tropics.
Risks to tropical crop yields in West Africa, Southeast Asia and Central and South America could be extensive

| Oppressive temperatures and accumulated heatwave duration ''very likely'' to directly impact human health, mortality and productivity
Substantial reductions in crop yield ''very likely''

|-
| Small islands
| Land of 60,000 less people exposed by 2150 on SIDS compared to impacts under 2°C of global warming
Risks for coastal flooding reduced by 20–80% for SIDS compared to 2°C of global warming

Freshwater stress reduced by 25%

Increase in the number of warm days for SIDS in the tropics

Persistent heat stress in cattle avoided

Loss of 70–90% of coral reefs

| Tens of thousands of people displaced owing to<br />
inundation of SIDSHigh risks for coastal floodingFreshwater stress reduced by 25% compared to<br />
2°C of global warming
<br/><br/>
Freshwater stress from projected aridity

Further increase of about 70 warm days per year

Persistent heat stress in cattle in SIDS

Loss of most coral reefs and weaker remaining structures owing to ocean acidification

| Substantial and widespread impacts through inundation of SIDS, coastal flooding, freshwater stress, persistent heat stress and loss of most coral reefs ( ''very likely'' )
|-
| Fynbos biome
| About 30% of suitable climate area lost<br />
( ''medium confidence'' )
| Increased losses (about 45%) of suitable climate area ( ''medium confidence'' )
| Up to 80% of suitable climate area lost<br />
( ''medium confidence'' )
|}
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