Talk:Climate change/Attributed and expected effects

Attributed and expected effects

This section relates to a previous discussion at Talk:Global warming/Archive 60#Rewrite of attributed and expected effects, and other changes

Large proposal moved here from Talk:Global warming

As I've said previously, I'm not happy with the quality of many areas of this article. Here are the changes I propose to the section on Attributed and expected effects:

• Addition of new information on regions and populations most affected
• Addition of neutrality and geographical balance tags
• Redirect from economics of global warming to economics of global warming#Impacts —Preceding unsigned comment added by Enescot (talk • contribs)

Addition of new information on regions and populations most affected

My proposed addition is in bold:

It is usually impossible to connect specific weather events to global warming. Instead, global warming is expected to cause changes in the overall distribution and intensity of events, such as changes to the frequency and intensity of heavy precipitation. Broader effects are expected to include glacial retreat, Arctic shrinkage including long-term shrinkage of Greenland ice sheet[63], and worldwide sea level rise. Some effects on both the natural environment and human life are, at least in part, already being attributed to global warming. A 2001 report by the IPCC suggests that glacier retreat, ice shelf disruption such as that of the Larsen Ice Shelf, sea level rise, changes in rainfall patterns, and increased intensity and frequency of extreme weather events are attributable in part to global warming.[64] Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.[65]

Regions that are likely to be most affected by global warming are the Arctic, Africa, small islands, and Asian megadeltas. Across all regions, some population groups are particularly at risk from the effects of global warming, e.g., the poor, young children, and the elderly.

Social and economic effects of global warming may be exacerbated by growing population densities in affected areas. Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.[66] A summary of probable effects and recent understanding can be found in the report made for the IPCC Third Assessment Report by Working Group II.[64] The newer IPCC Fourth Assessment Report summary reports that there is observational evidence for an increase in intense tropical cyclone activity in the North Atlantic Ocean since about 1970, in correlation with the increase in sea surface temperature (see Atlantic Multidecadal Oscillation), but that the detection of long-term trends is complicated by the quality of records prior to routine satellite observations. The summary also states that there is no clear trend in the annual worldwide number of tropical cyclones.[3]

Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71] and ocean oxygen depletion.[72] Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans.[73] CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in ocean acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004,[74] and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2.[3][75] Heat and carbon dioxide trapped in the oceans may still take hundreds of years to be re-emitted, even after greenhouse gas emissions are eventually reduced.[8] Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns and disruptions in food webs.[76] One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.[77] However, few mechanistic studies have documented extinctions due to recent climate change,[78] and one study suggests that projected rates of extinction are uncertain.[79]

Ref:

IPCC (2007). "Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)"]. IPCC, Geneva, Switzerland. pp. 104. [1]. Retrieved 2009-05-20. —Preceding unsigned comment added by Enescot (talk • contribs)

Is there a page reference for the two proposed sentences? I see p a reference to "pp. 104", but that appears to me to be the total length of AR4 including the appendix. ... Kenosis (talk) 20:59, 16 March 2010 (UTC)

Page 9. Enescot (talk) 21:57, 17 March 2010 (UTC)

OK, thanks. This material is already dealt with, on the level of specificity you suggest, at Effects_of_global_warming#Regions. I've no objection to it here too, but are practical limits to how much material we can fit into in this article. See WP:Summary style. ... Kenosis (talk) 19:01, 18 March 2010 (UTC)

Addition of neutrality and geographical balance tags

I do not think that this section is either neutral or sufficient in its geographical coverage of the topic. The description of some topics is biased:

• Health impacts
• New ocean trade routes

—Preceding unsigned comment added by Enescot (talk • contribs)

Health impacts

This is how health impacts are described at the moment:

Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.

[...] Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.

Additional expected effects include [...] changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71]

Compare this with the findings presented in the IPCC Synthesis Report:

• The health status of millions of people is projected to be affected through, for example, increases in malnutrition; increased deaths, diseases and injury due to extreme weather events; increased burden of diarrhoeal diseases; increased frequency of cardio-respiratory diseases due to higher concentrations of ground-level ozone in urban areas related to climate change; and the altered spatial distribution of some infectious diseases. {WGI 7.4, Box 7.4; WGII 8.ES, 8.2, 8.4, SPM}
• Climate change is projected to bring some benefits in temperate areas, such as fewer deaths from cold exposure, and some mixed effects such as changes in range and transmission potential of malaria in Africa. Overall it is expected that benefits will be outweighed by the negative health effects of rising temperatures, especially in developing countries. {WGII 8.4, 8.7, 8.ES, SPM}
• Critically important will be factors that directly shape the health of populations such as education, health care, public health initiatives, and infrastructure and economic development. {WGII 8.3, SPM}

There is an obvious difference between the two: the IPCC report is far less ambiguous that the article currently is. In particular, it says:

Climate change is projected to bring some benefits in temperate areas, such as fewer deaths from cold exposure, and some mixed effects such as changes in range and transmission potential of malaria in Africa. Overall it is expected that benefits will be outweighed by the negative health effects of rising temperatures, especially in developing countries. [emphasis added]

This statement of negative aggregate effects, plus the projection that those impacts will be worse in developing countries, is a key finding of the IPCC report. Yet, it is not mentioned in this article.

You see that there is an imbalance in the regional effects described for health impacts:

Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.

[...] Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.

The impacts in temperature regions are described, but the impacts in non-temperate regions are not described.

The coverage of health impacts is biased:

[...] Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.

[...] Additional expected effects include [...] changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71]

These impacts are mentioned:

• cold-related deaths
• heat exposure
• climate-dependent disease vectors
• malaria
• dengue fever

The IPCC report mentions:

• increases in malnutrition;
• increased deaths, diseases and injury due to extreme weather events;
• increased burden of diarrhoeal diseases;
• increased frequency of cardio-respiratory diseases due to higher concentrations of *ground-level ozone in urban areas related to climate change;
• altered spatial distribution of some infectious diseases
• fewer deaths from cold exposure
• some mixed effects such as changes in range and transmission potential of malaria in Africa.

I do not see that there's any reason for cold-related deaths, heat exposure, climate-dependent disease vectors, malaria, and dengue fever to have priority/more significance than:

• increases in malnutrition;
• increased deaths, diseases and injury due to extreme weather events; increased burden of diarrhoeal diseases;
• increased frequency of cardio-respiratory diseases due to higher concentrations of ground-level ozone in urban areas related to climate change

An estimate of the size and nature (positive or negative) is depicted in the IPCC Working Group II report, fig 8.3:

Ref:

Confalonieri, U., et al. (2007). "Human health. In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [M.L. Parry et al., Eds."]. Cambridge University Press, Cambridge, U.K., and New York, N.Y., U.S.A.. [2]. Retrieved 2009-05-20.

The negative impacts are larger than the positive impacts. The two largest impacts are (largest first): 1. Malnutrition, all negative (high confidence) 2. Malaria, mixed effects (v. high confidence). Increased deaths, diseases and injury due to extreme weather events, all negative (v. high conf)

The relative sizes of the impacts included in the article are:

• cold-related deaths (high conf) = ~1/5 the size of malnutrition impacts
• heat exposure= not mentioned
• climate-dependent disease vectors: not mentioned. "Change in the range of infectious disease vectors" is ~1/4 the size of malnutrition impacts
• malaria (v. high conf) = bit smaller than malnutrition
• dengue fever = not mentioned, perhaps included as part of the "infectious disease vector" indicator

Based on this figure, I believe that the article is currently biased towards impacts having:

• mixed effects rather than negative effects
• positive effects rather than negative effects
• smaller health impacts rather than large impacts

Suggested changes:

Based on their size, these impacts should be mentioned: 1. Increase in malnutrition 2. Increased deaths, diseases and injury due to extreme weather events 3. Increased frequency of cardio-respiratory diseases from changes in air quality. Increase in the burden of diarrhoeal diseases

For adequate balance across all regions, I suggest that these sentences are added:

With high confidence, IPCC (2007) projected that climate change would bring some benefits in temperate areas, such as fewer deaths from cold exposure, and some mixed effects such as changes in range and transmission potential of malaria in Africa. Health benefits were projected to be outweighed by the negative health effects of rising temperatures, especially in developing countries.

This addition would make existing parts on health impacts redundant.

Sentence shortened:

Existing revision:

Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and some adverse health effects from warmer temperatures.

Change to:

Other expected effects include water scarcity in some regions and increased precipitation in others, and changes in mountain snowpack.

Sentence deleted:

[...] Temperate regions are projected to experience fewer cold-related deaths but many more deaths from heat exposure.

Sentence shortened:

Existing sentence:

Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, changes in the range of climate-dependent disease vectors,[70] which have been linked to increases in the prevalence of malaria and dengue fever,[71] and ocean oxygen depletion

New sentence:

Additional anticipated effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, and ocean oxygen depletion —Preceding unsigned comment added by Enescot (talk • contribs)

New ocean trade routes

The existing revision states:

Additional anticipated effects include [...] new trade routes resulting from arctic shrinkage [...]

This is an impact that affects polar regions, coastal areas, and human industry, settlement, and society. Therefore, by its inclusion, we should have a balanced description of impacts affecting coastal areas, polar regions, and industry, settlements and society. Let's take coastal areas first. From the IPCC Synthesis report:

• Coasts are projected to be exposed to increasing risks, including coastal erosion, due to climate change and sea level rise. The effect will be exacerbated by increasing human-induced pressures on coastal areas (very high confidence). {WGII 6.3, 6.4, SPM}
• By the 2080s, many millions more people than today are projected to experience floods every year due to sea level rise. The numbers affected will be largest in the densely populated and low-lying megadeltas of Asia and Africa while small islands are especially vulnerable (very high confidence). {WGII 6.4, 6.5, Table 6.11, SPM}

As you can see, new trade routes are not mentioned. Based on this, I think that mentioning the opening of new trade routes is biased.

Polar regions from the IPCC Synthesis report:

• The main projected biophysical effects are reductions in thickness and extent of glaciers, ice sheets and sea ice, and changes in natural ecosystems with detrimental effects on many organisms including migratory birds, mammals and higher predators. {WGII 15.4, SPM}
• For human communities in the Arctic, impacts, particularly those resulting from changing snow and ice conditions, are projected to be mixed. {WGII 15.4, SPM}
• Detrimental impacts would include those on infrastructure and traditional indigenous ways of life. {WGII 15.4, SPM}
• In both polar regions, specific ecosystems and habitats are projected to be vulnerable, as climatic barriers to species invasions are lowered. {WGII 15.4, SPM}

As you can see, new trade routes are not mentioned. Based on this, I think that mentioning the opening of new trade routes is biased.

From the IPCC Synthesis report "Industry, settlements and society:"

• The most vulnerable industries, settlements and societies are generally those in coastal and river flood plains, those whose economies are closely linked with climate-sensitive resources and those in areas prone to extreme weather events, especially where rapid urbanisation is occurring. {WGII 7.1, 7.3, 7.4, 7.5, SPM}
• Poor communities can be especially vulnerable, in particular those concentrated in high-risk areas.

As you can see, new trade routes are not mentioned. Based on this, I think that mentioning the opening of new trade routes is biased.

My conclusion is that mentioning new trade routes is biased. It is biased in terms of its socio-economic effects being small relative to other socio-economic effects that are not mentioned. This is implied by the IPCC Synthesis Report's complete omission of the topic. Enescot (talk) 19:59, 15 March 2010 (UTC)

IMO, most or all of this suggested material is perhaps better suited for consideration at Effects_of_global_warming. No objection to trying some of the suggested condensations, but please try it one point at a time so the many participants have a chance to respond point by point. ... Kenosis (talk) 19:06, 18 March 2010 (UTC)

Okay. I suggest this change in how the article summarizes health impacts:

Proposed revision (changes in bold):

[...] A 2001 report by the IPCC suggests that glacier retreat, ice shelf disruption such as that of the Larsen Ice Shelf, sea level rise, changes in rainfall patterns, and increased intensity and frequency of extreme weather events are attributable in part to global warming.[64] Other expected effects include water scarcity in some regions and increased precipitation in others, and changes in mountain snowpack.[65]

Social and economic effects of global warming may be exacerbated by growing population densities in affected areas. It is expected that the health benefits of climate change (e.g., fewer deaths from cold exposure) will be outweighed by negative health effects (e.g., increased levels of malnutrition), especially in developing countries. A summary of probable effects and recent understanding can be found in the IPCC Fourth Assessment Report. According to this report, there is observational evidence for an increase in intense tropical cyclone activity [...]

Additional expected effects include sea level rise of 0.18 to 0.59 meters (0.59 to 1.9 ft) in 2090–2100 relative to 1980–1999,[3] new trade routes resulting from arctic shrinkage,[67] possible thermohaline circulation slowing, increasingly intense, in some locations, (but less frequent) hurricanes [68]and extreme weather events,[69] reductions in the ozone layer, changes in agriculture yields, and ocean oxygen depletion.[...]

Ref: [3]

Enescot (talk) 23:33, 19 March 2010 (UTC)