Geog 5: Tuvalu – Human Impact on the Islands

SPATIAL SCOPE

Tuvalu is a small nation and marine-coastal ecosystem. The Oceanic islands are located at 8º 52S, 179º 19E, which is east of Australia and north of Fij (Lal & Fortune 2000).

The name Tuvalu, “Eight islands”, refers to the eight islands originally inhibited. Now, Tuvalu is composed of four islands and five atolls. The capitol is Funafuti. The islands cover a total of 26 square kilometers, placing Tuvalu as the fourth smallest country in the world, only slightly larger than the Vatican. To put the size in perspective, Tuvalu is approximately 0.1 times the size of Washington DC (CIA “World Factbook”).

Image Source:

Figure 1. Map from the CIA World Factbook

Figure 2. Map from BBC News (http://news.bbc.co.uk/2/hi/asia-pacific/648373.stm).

HISTORY OF LAND
During World War II, the islands suffered minor blows from bombs. Some land was allocated for air landing strips, which took away from available farming-space, but after the war, agriculture resumed relatively unchanged (Cannon “History of Tuvalu”). Inhabitants go fishing nearby and farm coconuts on Tuvalu.

Image Source:

Figure 3. Bird’s Eye view of Funafuti, Tuvalu from UK Reuters (http://uk.reuters.com/article/2007/09/13/environment-tuvalu-dc-idUKSEO11194920070913)

Tuvalu is composed of coral islands. Native historians theorize that Tuvalu arose from coral build-up and subsiding volcanic rock. Currently, the highest point on the islands is 4 meters, about 15 feet above sea level (Lal & Fortune 2000). Tuvalu has always been relatively flat, and close to the ocean. The low-lying islands originally garnered no alarming attention.

However scientists fear that Tuvalu is at risk of submerging.

Starting in the late 20^th century, civilians became wary of rising sea levels, which are possibly attributed to global warming (Pollock “Atlantis Approaching”). Documentarian Elizabeth Pollack of Atlantis Approaching and writer Leslie Allen of the Smithsonian argue that Tuvalu is under risk of submerging underwater. Advocates of this theory further support the claim by citing record frequency of king tides and flooding.

On the other hand, counterarguments come from skeptics, who believe that natives are pushing the “Atlantis Agenda” as justification for a) loosening migration policy to New Zealand and more developed nations, b) boosting tourism from curious foreigners in the short-term. Researchers Paul Kent and Arthur Web attest that islands only appear to erode, but are in fact safely in tact (“The Dynamic Response of Reef Islands to Sea-Level Rise: Evidence from Multi-Decadal Analysis of Island Change in the Central Pacific”).

Also you might want to see this BBC article: http://www.bbc.co.uk/news/10222679.

HUMAN IMPACT ON TUVALU

Without siding with either side of the “Atlantis” debate, this blog will focus more on the relationship between humans and the Tuvaluan ecosystem. We will survey two significant points:

1. World War II and Tuvalu (Minor, Questionable Impact)
2.  Waste Management and Eutrophication (Large Impact)

World War II and Tuvalu: From 1941 to 1942, the islands were bombed by American aircrafts during World War II. Historian Brian Cannon reports that damage was “minimal” (ibid. “Tuvalu History”), however much wreckage was left on the beaches of Tuvalu and take away from the environment’s natural beauty.

There have been no concrete studies conducted to induce whether the WWII bombings disrupted the ecosystem or local food chain, however it is clearly seen that the landscape has been plagued by remnants of war machinery.

In addition, storms have caused people of various nationalities to abandon machinery and ships in Tuvalu. Almost little to no research has been published about the possible increase in metallic element and mineral amounts in the Oceanic water after WWII, which has made data-based projections of future effects difficult. However, we can present several images that attest for the physical presence of the material decay.

“Van Camp No. 1, December 1979, a Taiwanese ship wrecked in April 1972 during Cyclone Bebe.”

“Van Camp wreck, October 2005, showing how it has deteriorated over 25 years.”

Image Source:

Figure 4, 5 and 6. Photos of wreckage taken by Brian Cannon (http://www.tuvaluislands.com/ww2/wrecks.html).

Waste Management and Eutrophication of Ecosystem: Currently poor waste management has been a large issue in the marine-coastal ecosystem of Tuvalu. The waters have been polluted both by local inhabitants and global citizens. Internationally, storms wash up trash (including plastics and non-recyclable inorganic material) and unwanted chemicals to the Tuvaluan beaches. Locally, poorly-built septic tanks occasionally leak human waste into the waters. The surrounding ocean suffers from eutrophication, because the pollution adds too many minerals and nutrients. As a result, the coral of Tuvalu wither away. In addition, when eutrophication occurs, there tends to be an excessive growth of plants and algae, decreasing water transparency and changes in fish species composition.

“Such discharges in areas of limited water circulation and dilution are known to cause eutrophication of lagoons, which results in the growth of blue-green algae, changes in species composition, and decrease in biodiversity” (Lal, Saloa and & Uili “Economics of liquid waste management in Funafuti, Tuvalu”). Image source: Figure 7 and 8. Photos of damaged coral reefs obtained from Padma Lal, Kalesoma Saloa and Falealili Uili’s report Economics of liquid waste management in Funafuti, Tuvalu (ISSN 1818-5614) Here’s a point of interest, try to find: U. Kaly’s report “Tuvalu waste management project, ecological audit of Funafuti landfill: marine baseline surveys & assessment of site suitability”.

For further investigation, one can also examine the effects of “Fishing and Coconut Farming” or “Human Overpopulation” as other impacts on the Tuvaluan ecosystem. Several resources are listed in our Additional Reading section.

BENEFITS FROM THE ECOSYSTEM

Fishery and coconut farming are primary means of sustenance and economic profit for inhabitants of Tuvalu. Currently Tuvalu reaps of the benefit of the Economic Exclusive Zone (United Nations Convention on the Law of the Sea - Part V), which gives Tuvaluans control of all marine resources in a 200 nautical mile radius from Funafuti.

In extension of the marine-coastal ecosystem, Tuvalu houses a coral reef community, so this increases the value of the island territory. The NOAA (National Oceanic and Atmospheric Assocation) reports that more than 25% of marine fish species are endemic to coral reefs, which are in themselves rare and few in marine ecosystems (Bryant "Reefs at Risk: A map-based indicator of potential threats to the world's coral reefs").

Notably, Tuvalu is home to over 10,600 people (CIA “World Factbook”). In the late 1800s, European merchants and whalers brought much economic activity to Tuvalu. Then in 1877, Tuvalu (then known as Ellice Islands) was colonized by the British.  The islands were settled by foreign fishermen and sea merchants, who joined the native Polynesian islanders.  Later, in October 1987, Tuvalu became an independent nation (Cannon “Tuvalu History”). 

Now, Tuvalu enjoys moderate income from tourism, so there is currently a larger incentive to maintain the tropical beauty of this marine-coastal ecosystem (Lockwood “Globalization and Culture Change in the Pacific Islands”).

PROTECTED AREAS AND STATUS
Since 1996, the Tuvalu Conservation Areas Act has protected 35.95 square kilometers of land. Most notably, there is one official protected area in Funafuti, and a proposed site in Vaitupu. Other islands have sites which also set out land for wildlife (see table below). According to the International Union for Conservation of Nature (IUCN), Tuvalu is home to 121 plant, 19 bird, 22 mammal, 5 reptile and 189 fish species (IUCN “Red List 2008”).

Funafuti Conservation Area
Funafuti fosters high biodiversity in the marine-coastal ecosystem species, which include coconut crabs, pan-tropical spotted dolphins, pygmy killer whales, brown boobies, white tern and others (“Funafuti Marine Conservation Area, Tuvalu: Report of the Bird Survey”). Despite being a nature conservancy site, this area also allows for snorkeling and scuba diving.

Video about Funafuti Conservation Area:

(Source: http://www.youtube.com/watch?v=B_J4fBPReNA)

For further information, you may also wish to consult: http://www.timelesstuvalu.com/tuvalu/export/sites/TTO/Attractions/funafuti_conservation_area.html

Vaitupu Conservation Area

This conservation area was proposed in 2003, but not yet designated as official site. Plans parallel those at Funafuti (UNFCCC and UNDP “Tuvalu’s National Adaption Programme of Action”).

There was also a data table released by the Government of Tuvalu, managed under the Millenium Development Goal Taskforce and United Nations Development Programme (UNDP) in May 2011, which comprehensively listed Conservation Areas in Tuvalu. It is displayed below:

(source: http://www.undp.org.fj/pdf/MDG%20Report/MDG(tuvalu)%20web.pdf) 

FUTURE & SUGGESTIONS FOR SUSTAINABILITY

It appears that Tuvalu as a coastal-marine ecosystem has heavily been impacted by human actions, both from the local and international community. We can project that the coral of Tuvalu will continue to be destroyed by eutrophication, unless preventive action is taken or pollutants stop being dumped into the sea. The coastline may continue to shrink as ocean levels rise, but by recognizing that extreme climate change is partly anthropogenic, then humans can slow down the rate of polar-ice cap melting and other inducers of rising ocean levels. In the future, perhaps there would be research conducted to determine if the abandoned machinery has added minerals and metals to the sands of Tuvalu or in someway disrupted animal life. Fortunately, the conservation sites are boon to Tuvalu and will mitigate some of the harm done to the marine-coastal ecosystem.

So what can be done to maintain balance between people and the ecosystem? In lieu of a paragraph, a brief outline of recommendations is provided below:

1. Establish an awareness and education campaign
1. to plan for future displaced people of Tuvalu if island made uninhabitable by rising sea levels
2. to reduce trash and waste polluting the waters/oceans
2. Fix the waste systems to fight off eutrophication of marine ecosystem and destruction of coral reefs
3. Remove military machinery, wreckage and debris on beach to prevent additional decay and pollution into the coastal-marine ecosystem.
4. Focus on conservation of islands, convert soils to sustainable agriculture to feed island population for future.

Note on Global Warming and Sinking

If the “Atlantis theory” is correct, then the matter of human migration trumps all aforementioned concerns. Tuvaluans must prepare to evacuate the islands eventually, if this ecosystem is not stabilized and made self-sustainable.

If the theory that global warming upholds, then polar ice caps will melt at a faster rate, sea levels will rise and Tuvalu will be at risk of sinking. This threat could lead to many displaced peoples, if lands submerge deeper. In this situation, future migration should be planned and regulated by Tuvaluan and neighboring-countries government. In the worst case scenario, extreme climate change could lead to:

1. Unused soils and desertification, or tropical plants overrunning the islands.
2. Future modern Atlantis, as described by scientists and public officials.

On the other hand, can humans prevent Tuvalu from becoming sunken islands? The Intergovernmental Panel on Climate Change (IPCC) claims that climate change is highly anthropogenic. For your interest, a table of the points IPCC made are attached to this blog (see Appendix).

Reference Sources:

Allen, L. 2004. "Will Tuvalu Disappear Beneath the Sea?" Smithsonian. 35.5 (2004): 44-53. Print.

"High Tides Threaten Tuvalu." BBC News: World: Asia-Pacific. BBC, 18 Feb. 2000. Web. 08 Nov. 2012. <http://news.bbc.co.uk/2/hi/asia-pacific/648373.stm>.

Cannon, Brian. "Tuvalu History." Tuvalu History. BRC Online, 18 Sept. 2012. Web. 11 Nov. 2012. <http://www.tuvaluislands.com/history.htm>.
Bryant, Dirk G. Reefs at Risk: A Map-Based Indicator of Threats to the World's Coral Reefs. Washington, D.C: World Resources Institute, 1998. Print.

Kench, Paul and Arthur Web. The Dynamic Response of Reef Islands to Sea-Level Rise: Evidence from Multi-Decadal Analysis of Island Change in the Central Pacific. Elsevier B.V, 2012. < http://www.sciencedirect.com/science/article/pii/S0921818110001013>.

Lal, Brij V, and Kate Fortune. The Pacific Islands: An Encyclopedia. Honolulu: University of Hawai'i Press, 2000. Print.

Lal, Padma, Kalesoma Saloa and Falealili Uili. “Economics of liquid waste management in Funafuti, Tuvalu”. Iwp-pacific Technical Report. Apia, Samoa: South Pacific Regional Environment Programme, SPREP, 2000. Print.

Lockwood, Victoria S. Globalization and Culture Change in the Pacific Islands. Upper Saddle River, N.J: Pearson Education, 2004. Print.

Pollock, Elizabeth. Atlantis Approaching. Milwaukee, WI: Blue Marble Productions, 2006. Film.

Solomon, Susan. Climate Change 2007: The Physical Science Basis : Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press, 2007. Print.

Funafuti Marine Conservation Area, Tuvalu: Report of the Bird Survey (August 31 - September 11, 1998). Apia, Samoa: South Pacific Regional Environment Programme, 1998. Print.

IUNC Red List of Threatened Animals. Gland: IUCN, 2008. Print.

United Nations Framework Convention on Climate Change. Tuvalu’s National Adaptation Programme of Action. United Nations Development Programme , 2007. Print

World Factbook. Washington, D.C: U.S. Central Intelligence Agency, 2012. <https://www.cia.gov/library/publications/the-world-factbook/geos/tv.html>.

Additional Reading:
Baarsch, Florent, and Lan M. Berg. "Warming Oceans and Human Waste Hit Tuvalu's Sustainable Way of Life." Guardian UK: Poverty Matters Blog. Guardian Uk, Bill and Melinda Gates Foundation, 4 Mar. 2011. Web. 27 Oct. 2012. <http://www.guardian.co.uk/global-development/poverty-matters/2011/mar/04/tuvalu-sustainable-way-of-life-disappears>. Online Resource.

Faaniu, Simati, and Hugh Laracy. Tuvalu, a History. Suva, Fiji: Institute of Pacific Studies and Extension Services, University of the South Pacific and the Ministry of Social Services, Government of Tuvalu, 1983. Print.

Fisher, P B. Reframing Global Climate Change: Achieving Human Security for Vulnerable Communities. Irvine, Calif: University of California, Irvine, 2009. Print.

Head, Lesley. "Cultural Ecology: Adaptation - Retrofitting a Concept?" Progress in Human Geography. 34.2 (2010): 234-242. Print.

Ralston, Holley, Britta Horstmann, and Carina Holl. Climate Change: Challenges Tuvalu. Bonn: Germanwatch, 2004. Print.

Appendix:

Source: IPCC “Climate Change 2007: The Physical Science Basis”

Result	Region	Likelihood	Factors contributing to likelihood assessment
Surface temperature
Warming during the past half century cannot be explained without external radiative forcing	Global	Extremely likely (>95%)	Anthropogenic change has been detected in surface temperature with very high significance levels (less than 1% error probability). This conclusion is strengthened by detection of anthropogenic change in the upper ocean with high significance level. Upper ocean warming argues against the surface warming being due to natural internal processes. Observed change is very large relative to climate-model simulated internal variability. Surface temperature variability simulated by models is consistent with variability estimated from instrumental and palaeorecords. Main uncertainty from forcing and internal variability estimates (Sections 9.4.1.2, 9.4.1.4, 9.5.1.1, 9.3.3.2,9.7).
Warming during the past half century is not solely due to known natural causes	Global	Very Likely	This warming took place at a time when non-anthropogenic external factors would likely have produced cooling. The combined effect of known sources of forcing would have been extremely likely to produce a warming. No climate model that has used natural forcing only has reproduced the observed global warming trend over the 2nd half of the 20th century. Main uncertainties arise from forcing, including solar, model-simulated responses and internal variability estimates (Sections 2.9.2, 9.2.1,9.4.1.2, 9.4.1.4; Figures 9.5, 9.6, 9.9).
Greenhouse gas forcing has been the dominant cause of the observed global warming over the last 50 years.	Global	Very likely	All multi-signal detection and attribution studies attribute more warming to greenhouse gas forcing than to a combination of all other sources considered, including internal variability, with a very high significance. This conclusion accounts for observational, model and forcing uncertainty, and the possibility that the response to solar forcing could be underestimated by models. Main uncertainty from forcing and internal variability estimates (Section 9.4.1.4; Figure 9.9).
Increases in greenhouse gas concentrations alone would have caused more warming than observed over the last 50 years because volcanic and anthropogenic aerosols have offset some warming that would otherwise have taken place.	Global	Likely	Estimates from different analyses using different models show consistently more warming than observed over the last 50 years at the 5% significance level. However, separation of the response to non-greenhouse gas (particularly aerosol) forcing from greenhouse gas forcing varies between models (Section 9.4.1.4; Figure 9.9).
There has been a substantial anthropogenic contribution to surface temperature increases in every continent except Antarctica since the middle of the 20th century	Africa, Asia, Australia, Europe, North America and South America	Likely	Anthropogenic change has been estimated using detection and attribution methods on every individual continent (except Antarctica). Greater variability compared to other continental regions makes detection more marginal in Europe. No climate model that used natural forcing only reproduced the observed continental mean warming trend over the second half of the 20th century. Uncertainties arise because sampling effects result in lower signal-to-noise ratio at continental than at global scales. Separation of the response to different forcings is more difficult at these spatial scales (Section 9.4.2; FAQ 9.2, Figure 1).
Early 20th-century warming is due in part to external forcing.	Global	Very Likely	A number of studies detect the influence of external forcings on early 20th-century warming, including a warming from anthropogenic forcing. Both natural forcing and response are uncertain, and different studies find different forcings dominant. Some studies indicate that internal variability could have made a large contribution to early 20th-century warming. Some observational uncertainty in early 20th-century trend (Sections 9.3.3.2, 9.4.1.4; Figures 9.4, 9.5).
Result	Region	Likelihood	Factors contributing to likelihood assessment
Surface temperature
Pre-industrial temperatures were influenced by natural external forcing (period studied is past 7 centuries)	NH (mostly extratropics)	Very Likely	Detection studies indicate that external forcing explains a substantial fraction of inter-decadal variability in NH temperature reconstructions. Simulations in response to estimates of pre-industrial forcing reproduce broad features of reconstructions. Substantial uncertainties in reconstructions and past forcings are unlikely to lead to a spurious agreement between temperature reconstructions and forcing reconstructions as they are derived from independent proxies (Section 9.3.3; Figures9.4, 6.13).
Temperature extremes have changed due to anthropogenic forcing	NH land areas and Australia combined.	Likely	A range of observational evidence indicates that temperature extremes are changing. An anthropogenic influence on the temperatures of the 1, 5, 10 and 30 warmest nights, coldest days and coldest nights annually has been formally detected and attributed in one study, but observed change in the temperature of the warmest day annually is inconsistent with simulated change. The detection of changes in temperature extremes is supported by other comparisons between models and observations. Model uncertainties in changes in temperature extremes are greater than for mean temperatures and there is limited observational coverage and substantial observational uncertainty (Section 9.4.3).
Free atmosphere changes
Tropopause height increases are detectable and attributable to anthropogenic forcing (latter half of the 20th century)	Global	Likely	There has been robust detection of anthropogenic influence on increasing tropopause height. Simulated tropopause height increases result mainly from greenhouse gas increases and stratospheric ozone decreases. Detection and attribution studies rely on reanalysis data, which are subject to inhomogeneities related to differing availability and quality of input data, although tropopause height increases have also been identified in radiosonde observations. Overall tropopause height increases in recent model and one reanalysis (ERA-40) appear to be driven by similar large-scale changes in atmospheric temperature, although errors in tropospheric warming and stratospheric cooling could lead to partly spurious agreement in other data sets (Section 9.4.4.2; Figure 9.14).
Tropospheric warming is detectable and attributable to anthropogenic forcing (latter half of the 20th century)	Global	Likely	There has been robust detection and attribution of anthropogenic influence on tropospheric warming, which does not depend on including stratospheric cooling in the fingerprint pattern of response. There are observational uncertainties in radiosonde and satellite records. Models generally predict a relative warming of the free troposphere compared to the surface in the tropics since 1979, which is not seen in the radiosonde record (possibly due to uncertainties in the radiosonde record) but is seen in one version of the satellite record, although not others (Section 9.4.4).
Simultaneous tropospheric warming and stratospheric cooling due to the influence of anthropogenic forcing has been observed (latter half of the 20th century)	Global	Very Likely	Simultaneous warming of the troposphere and cooling of the stratosphere due to natural factors is less likely than warming of the troposphere or cooling of the stratosphere alone. Cooling of the stratosphere is in part related to decreases in stratospheric ozone. Modelled and observational uncertainties as discussed under entries for tropospheric warming with additional uncertainties due to stratospheric observing systems and the relatively poor representations of stratospheric processes and variability in climate models (Section 9.4.4).

b)

Result	Region	Likelihood	Factors contributing to likelihood assessment
Ocean changes
Anthropogenic forcing has warmed the upper several hundred metres of the ocean during the latter half of the 20th century	Global (but with limited sampling in some regions)	Likely	Robust detection and attribution of anthropogenic fingerprint from three different models in ocean temperature changes, and in ocean heat content data, suggests high likelihood, but observational and modelling uncertainty remains. 20th-century simulations with MMD models simulate comparable ocean warming to observations only if anthropogenic forcing is included. Simulated and observed variability appear inconsistent, either due to sampling errors in the observations or under-simulated internal variability in the models. Limited geographical coverage in some ocean basins (Section 9.5.1.1; Figure 9.15).
Anthropogenic forcing contributed to sea level rise during the latter half 20th century	Global	Very likely	Natural factors alone do not satisfactorily explain either the observed thermal expansion of the ocean or the observed sea level rise. Models including anthropogenic and natural forcing simulate the observed thermal expansion since 1961 reasonably well. Anthropogenic forcing dominates the surface temperature change simulated by models, and has likely contributed to the observed warming of the upper ocean and widespread glacier retreat. It is very unlikely that the warming during the past half century is due only to known natural causes. It is therefore very likely that anthropogenic forcing contributed to sea level rise associated with ocean thermal expansion and glacier retreat. However, it remains difficult to estimate the anthropogenic contribution to sea level rise because suitable studies quantifying the anthropogenic contribution to sea level rise and glacier retreat are not available, and because the observed sea level rise budget is not closed (Table 9.2; Section 9.5.2).
Circulation
Sea level pressure shows a detectable anthropogenic signature during the latter half of the 20th century	Global	Likely	Changes of similar nature are observed in both hemispheres and are qualitatively, but not quantitatively consistent with model simulations. Uncertainty in models and observations. Models underestimate the observed NH changes for reasons that are not understood, based on a small number of studies. Simulated response to 20th century forcings is consistent with observations in SH if effect of stratospheric ozone depletion is included (Section 9.5.3.4; Figure 9.16).
Anthropogenic forcing contributed to the increase in frequency of the most intense tropical cyclones since the 1970s	Tropical regions	More likely than not (>50%)	Recent observational evidence suggests an increase in frequency of intense storms. Increase in intensity is consistent with theoretical expectations. Large uncertainties due to models and observations. Modelling studies generally indicate a reduced frequency of tropical cyclones in response to enhanced greenhouse gas forcing, but an increase in the intensity of the most intense cyclones. Observational evidence, which is affected by substantial inhomogeneities in tropical cyclone data sets for which corrections have been attempted, suggests that increases in cyclone intensity since the 1970s are associated with SST and atmospheric water vapour increases (Section 3.8.3, Box 3.5 and Section 9.5.2.6).
Precipitation, Drought, Runoff
Volcanic forcing influences total rainfall	Global land areas	More likely than not (>50%)	Model response detectable in observations for some models and result supported by theoretical understanding. However, uncertainties in models, forcings and observations. Limited observational sampling, particularly in the SH (Section 9.5.4.2; Figure 9.18).
Increases in heavy rainfall are consistent with anthropogenic forcing during latter half 20th century	Global land areas (limited sampling)	More likely than not (>50%)	Observed increases in heavy precipitation appear to be consistent with expectations of response to anthropogenic forcing. Models may not represent heavy rainfall well; observations suffer from sampling inadequacies (Section 9.5.4.2).
Result	Region	Likelihood	Factors contributing to likelihood assessment
Precipitation, Drought, Runoff
Increased risk of drought due to anthropogenic forcing during latter half 20th century	Global land areas	More likely than not (>50%)	One detection study has identified an anthropogenic fingerprint in a global Palmer Drought Severity Index data set with high significance, but the simulated response to anthropogenic and natural forcing combined is weaker than observed, and the model appears to have less inter-decadal variability than observed. Studies of some regions indicate that droughts in those regions are linked either to SST changes that, in some instances, may be linked to anthropogenic aerosol forcing (e.g., Sahel) or to a circulation response to anthropogenic forcing (e.g., southwest Australia). Models, observations and forcing all contribute uncertainty (Section 9.5.3.2).
Cryosphere
Anthropogenic forcing has contributed to reductions in NH sea ice extent during the latter half of the 20th century	Arctic	Likely	The observed change is qualitatively consistent with model-simulated changes for most models and expectation of sea ice melting under arctic warming. Sea ice extent change detected in one study. The model used has some deficiencies in arctic sea ice annual cycle and extent. The conclusion is supported by physical expectations and simulations with another climate model. Change in SH sea ice probably within range explained by internal variability (Section 9.5.5.1).
Anthropogenic forcing has contributed to widespread glacier retreat during the 20th century	Global	Likely	Observed changes are qualitatively consistent with theoretical expectations and temperature detection. Anthropogenic contribution to volume change difficult to estimate. Few detection and attribution studies, but retreat in vast majority of glaciers consistent with expected reaction to widespread warming (Section 9.5.5.3).