Climate change will affect the distribution and diversity of marine organisms

Climate change will force marine organisms towards the poles, but would they be safe there? 

Human activities such as emissions from the use of fossil fuels, rampant urbanisation, deforestation, and modern agricultural practices, are all altering the earth’s climate in an unprecedented scale. Climate change not only occurs in the land, but also in water bodies. Studies have indicated that since the 1950s, the amount of heat stored in the ocean (ocean heat) has increased considerably. Besides, ocean temperatures have increased throughout the world since the advent of the twentieth century, with the past three decades recording the highest temperatures since the measurements began.

 A major consequence of increase in ocean temperatures is the corresponding decrease in dissolved oxygen levels. This phenomenon is predicted to significantly disturb marine ecosystems. Recent research by a group of American and German scientists revealed the consequences of oceanic climate change on a range of fish and crustacean species in the North Atlantic with different levels of tolerance towards heat and oxygen levels. The researchers'  climate models predict substantial warming and deoxygenation throughout most of the upper ocean by the end of this century which in turn will affect the distribution  of marine  creatures. Their studies reveal that warming of water and oxygen depletion would force the organisms to migrate towards the pole due to deficiency of the original native waters to sustain their energy requirements. The scientists predict that even the waters towards the pole would have reduced oxygen levels, meaning the survival of the migrants could be precarious even there. Furthermore, this movement could alter the ecosystems in the polar waters due to many factors including competition from the migrants which may alter species ecologies.

References

http://www.sciencemag.org/content/348/6239/1132.abstract

Deutsch C, Ferrel A, Seibel B, Pörtner HO, & Huey RB (2015). Ecophysiology. Climate change tightens a metabolic constraint on marine habitats. Science (New York, N.Y.), 348 (6239), 1132-5 PMID: 26045435

Global Temperature Rise and Human Health - How is the World Coping?

Global temperatures have been on the rise since the Industrial Age due to human activity such as the emissions of greenhouse gases from fossil fuel burning, large-scale deforestation, expansion of urban areas where vegetation cover is replaced by artificial heat retaining materials such as asphalt and concrete, some agricultural practices, and waste management activities. Data from the National Climatic Data Centre that  maintains the world's largest climate data archive indicate that the average global temperature across land surfaces was 1.68°C (3.02°F) above the 20th century average of 3.2°C (37.8°F) . To put things in perspective, February 2015 was much warmer than February 2014.

 Epidemiological studies in different parts of the world have unequivocally shown a strong link between high temperature and mortality, which is a public health concern. The magnitude of the problem will only escalate as the global mean temperature continues to increase causing extreme heat events in large geographical areas. Approximately 650 deaths per year occur in United States due to heat events, which account for more fatalities than any other weather hazard. Males outnumber females in deaths cause by extreme heat events.

Vulnerable population for heat-related deaths

 Although the human body can tolerate changes in temperature by the process of thermoregulation, whereby it can protect itself from extremes in ambient temperature, there are limits. Importantly, infants and the elderly particularly those with health conditions such as cardiovascular disease, cerebrovascular disease, neurological diseases, diabetes, renal disease and respiratory disease are particularly vulnerable to mortality due to increase in ambient temperature. However, many studies indicate that there is a lack of risk perception among the population to heat-related deaths.

Global disparity in knowledge pertaining to extreme heat, its consequences, and public health responses  

 In many developed nations, data on temperature rise and its consequences on health are often readily available due to good documentation of historical temperature records and epidemiological research in these areas. Heat vulnerability maps (Heatwave maps) now exist for many areas in developed countries- particularly cities, that help identify regions that are at risk for extreme heat events. In many such places, Heat response plans that help prepare communities for heath rated illnesses exist.

However, developing nations lag behind both in research as well as public health strategies to mitigate extreme heat events. A plethora of factors such as  knowledge gaps, defective record keeping and poor research (death records, which list causes of death are often unreliable particularly in rural areas), archaic technology, lack of funds, corruption, poor public health initiatives, all lead to poor knowledge  or ignorance  pertaining to the health effects of extreme temperature. The health implications of extreme heat  is likely to be  far more pronounced in the developing countries, which are often subject to extreme climate change compared to the developed countries, but is likely staying under the radar.

Here through the pages of Ecoratorio, we have often highlighted the dangers of human activities on the environment and the need for global, personal, and corporate environmental stewardship. Specifically in the context of heat-related illnesses and deaths, a cohesive understanding of the environmental impact on human health, identification of vulnerable populations, expert recommendations on public behaviour and timely communication of these recommendations, generating public awareness through mass media of health-related illnesses and deaths, and enforcement of mitigation steps in the general public is critical. With extreme heath events anticipated to rise in the coming years due to climate change, population increase, and increase in ageing population, it is crucial that  scientific, political and public health action should take place to manage this important issue.

Useful Facts about Heat-related illnesses

• Although many studies have stressed infants and elderly as being most vulnerable to heat –related illnesses and death, other high-risk groups include young children, older adults (people over 65 years) and people who engage in strenuous activities outdoors.
• Extreme heat events disproportionately harm vulnerable populations.
• The majority of heat-related deaths are preventable.
• During periods of extreme heat, heat-related illnesses can be prevented by using air-conditioning, avoiding strenuous outdoor activities, drinking adequate amounts of fluid, wearing lightweight clothing, and avoiding alcohol consumption. 
•  Heat Response plans should be in place before extreme heat events occur.
• Major inequalities exist between developed and the developing nations in the awareness of heat- related illnesses, the contributory factors, and public health initiatives.

References:

1. http://www.ncdc.noaa.gov/sotc/global/
2.  http://monash.edu/news/show/heatwave-map-reveals-melbournes-most-vulnerable-postcodes
3.  Madrigano, J., Ito, K., Johnson, S., Kinney, P., & Matte, T. (2015). A Case-Only Study of Vulnerability to Heat Wave–Related Mortality in New York City (2000–2011) Environmental Health Perspectives DOI: 10.1289/ehp.1408178http://dx.doi.org/10.1289/ehp.1408178">10.1289/ehp.1408178>
4. Kim, C., Lim, Y., Woodward, A., & Kim, H. (2015). Heat-Attributable Deaths between 1992 and 2009 in Seoul, South Korea PLOS ONE, 10 (2) DOI: 10.1371/journal.pone.0118577http://dx.doi.org/10.1371/journal.pone.0118577">10.1371/journal.pone.0118577>
5. http://www.epa.gov/climatechange/science/indicators/health-society/heat-deaths.html
6. Bobb, J., Peng, R., Bell, M., & Dominici, F. (2014). Heat-Related Mortality and Adaptation to Heat in the United States Environmental Health Perspectives DOI: 10.1289/ehp.1307392http://dx.doi.org/10.1289/ehp.1307392">10.1289/ehp.1307392>
7. http://www.medscape.com/viewarticle/806947

A small step for koalas

I have been following certain developments on the koala front in Australia. The marsupial is an icon associated with Australia- and is also well known for its predilection for eucalyptus and sleep.

After a decline in the wild population (to approx. around 200,000 according to government figures), Tony Burke (Australia’s Environment Minister), following a Senate report, has listed koalas as ‘vulnerable’ species last week. However, the tag will be restricted to certain areas- i.e Queensland, New South Wales (both states experienced a heavy decline in population), and Australian Capital Territory (which now has no wild koalas), which is another example of effective lobbying by the industries concerned as both Victoria (which has the distinct Strzelecki koalas, most of which are in private properties) and South Australia are not included (Burke claims that there are large koala populations in these two states). Whilst NSW welcomed this development, the Queensland Premier, Campbell Newman, is disgruntled, labelling the move as a ‘mindless green tape’ and threat to the employment market and development in the state.

The Senate report associated the population decline with habitat destruction (mainly by coal mining, logging, and housing developments), climate change (drought and extreme weather resulting in bushfires), accidents (road-kill), attacks by dogs (especially in summer when they venture into gardens to drink from swimming pools and water bowls), and disease (notably: Chlamydia). In the case of bushfires, koalas’ slow-moving nature prevents them from escaping from fires.

The question now remains as to what will be done proactively to ensure that the koala isn’t driven to extinction.


Image source: BSPI/Corbis
Sources:


http://www.smh.com.au/environment/conservation/koalas-to-be-listed-as-threatened-amid-rapid-decline-20120426-1xo22.html

http://www.smh.com.au/environment/animals/youd-be-lucky-to-see-one-bid-to-protect-the-koala-20120430-1xv64.html#ixzz1tXMalDBm

http://www.smh.com.au/environment/conservation/koalas-get-some-protections-from-developers-20120430-1xtps.html#ixzz1tXMresPs

http://www.businessreviewaustralia.com/business_leaders/mining-boom-contributing-to-koala-decline

http://www.foxnews.com/scitech/2012/04/30/australian-govt-to-protect-koala-bears/#ixzz1tXLgGhYn

http://www.theaustralian.com.au/national-affairs/koala-listing-another-example-of-government-greentape-says-campbell-newman/story-fn59niix-1226342948508

http://www.environment.gov.au/biodiversity/threatened/pubs/guidelines-species.pdf

http://www.canberratimes.com.au/environment/koalas-protected-in-north-but-need-managing-in-south-20120430-1xu13.html#ixzz1tXM4mhNF

http://www.canberratimes.com.au/national/qld-slams-koala-move-as-mindless-green-tape-20120430-1xvfm.html#ixzz1tXN8svj7

http://www.abc.net.au/local/photos/2012/04/30/3491805.htm

http://www.abc.net.au/local/stories/2012/04/30/3492033.htm

http://www.abc.net.au/news/2012-04-30/koala-listed-as-vulnerable/3980216/?site=sydney
http://www.abc.net.au/news/2012-04-30/no-protection-for-victoria27s-koalas/3981160?section=vic

http://www.theage.com.au/victoria/victorian-koalas-left-out-in-the-cold-20120430-1xv2b.html#ixzz1tXMRlXGf

http://news.ninemsn.com.au/national/8459541/nsw-govt-welcomes-koala-listing

Migratory bird species in the UK

I will always maintain that the loveliest spring and summer are experienced in England. Apart from the profusion of flowers and exceptionally pleasant weather, there was always a persistent backdrop of birdsong, regardless of whether I was in town or country, sidewalks or fens. This chorus now stands the danger of disappearing from the British Isles, as explained in the 2010 Breeding Bird Survey (BBS) report which lists the statistics of bird population from 1995 to 2010. But first the good news…

Good news:

- Two warbler species have reached their highest numbers in 15 years: Blackcap (+73%) and Whitethroat (+25%). The Whitethroat population had plummeted in 1969 due to the drought in Sahel (the arid zone south of Sahara where they spend winter), but have now risen probably due to increased rainfall in the region.

-Chiffchaff (+52%).

Bad news:
10 species have experienced a decline in population numbers between 1995 and 2010. Of these, 8 are annual migratory species which spend autumn and winter in sub-Saharan Africa and return to the UK in spring and summer for breeding (viz, turtle dove, cuckoo, nightingale, wood warbler, whinchat, yellow wagtail, pied flycatcher, and spotted flycatcher).

-Turtle dove: a decline of 74%, with 2009-2010 experiencing a slump of -21%.
-Nightingales: decline of -63%, with a -27% fall in the 2010 level from the 2009 levels. Now seen mainly in SE England.
-Wood warblers: -60%
-Whinchats: -55%
- Yellow wagtails: -55%
- Pied flycatcher: -51%
- Cuckoo: decline of -48%; Now more commonly sighted in Scotland than in England.
- Spotted flycatcher: -47%
The two non-migratory species which have shown a marked decline are:
- willow tit (-76%)
-grey partridge (-54%)

The trend is that relatively short-distance migrants (such as Blackcap and Chiffchaff which fly down to southern Spain and Northern Africa, without crossing Sahara) are doing better, whilst those that travel further (such as Turtle Dove, Cuckoo, and Nightingale) are showing a steady decline in population. The reasons are postulated to be habitat destruction (due to anthropogenic factors), desertification, hunting, and repercussions of climate change- but it is most likely to be a combination of many factors. Since the bird species’ migration corridor covers many regions/countries during the course of the year, the manifestation of any such factor anywhere could act as a leverage point.

* I apologise for any mistakes which might occur when one had taken a cocktail of medicines (am battling a wrist sprain, (another) bout of food poisoning, and an exceptionally torturous flu- all at the same time).

Image source: Scott Barrow/Corbis

Effect of climate change on human morbidity and mortality and sea levels

Climate change has been resulting in quite a many detrimental manifestations which tend to have a domino effect: fluctuations in temperature and precipitation (resulting in climate variability), as well as extreme manifestations such as drought, storms, rise in sea levels, and frequent severe weather events.

Consider the research by Grinsted et al (2009) who used a ‘physically plausible four parameter linear response equation’ to relate nearly 2,000 years of global temperatures and sea level. Assuming that this relationship holds from 200 to 2100 AD, IPCC’s temperature scenarios and reconstructed past sea level scenarios were used to visualise future sea level scenarios. The result suggests that climate change will lead to a 0.9-1.3 m change in sea level between 2090-2099. This bodes a certain flooding of low lying coastal regions and islands. Island countries such as Maldives would practically cease to exist. Whilst countries such as Bangladesh may not face such obliteration, such a sea level rise would flood 1/3rd of the country, displacing millions of humans and severely affecting agriculture, irrigation, and livestock.

Climate change also has a perceptible impact on human morbidity and mortality (Patz et al, 2005). Climate fluctuations have been linked to diseases and ailments- the evident effects of heat/cold (which, for instance, follows a U-shaped dose-response function with increased mortality in the extreme heat and cold), traumatic physical and mental ailments, and even cardiovascular and respiratory illnesses. This even results in altered transmission of infectious diseases (for instance, changes in temperature has been associated with salmonellosis in Europe and cholera in the ‘American south-west’; whilst, changes in rainfall has been associated with Rift valley fever in East Africa, and Hantavirus pulmonary syndrome and cholera in the American south-west and Bangladesh). When one factors in the effects of climate change on air pollution and the greater ecosystem, the result is quite chaotic. If the future projections of climate change are plausible, then it is likely that these health risks may rise significantly. The ‘potentially vulnerable’ regions includes the temperate latitudes (which may warm disproportionately), and the regions in and around the Pacific and Indian oceans (substantial rainfall variability).

But even though the economic North/developed countries are responsible for most of the greenhouse gas emissions, the damaging effects of their actions are most perceived in the poor countries of the South which has (as of yet) contributed least towards the GHG emissions.

References:
Patz, J., Campbell-Lendrum, D., Holloway, T., & Foley, J. (2005). Impact of regional climate change on human health Nature, 438 (7066), 310-317 DOI: 10.1038/nature04188

Grinsted, A., Moore, J., & Jevrejeva, S. (2009). Reconstructing sea level from paleo and projected temperatures 200 to 2100 ad Climate Dynamics, 34 (4), 461-472 DOI: 10.1007/s00382-008-0507-2

Paper of the Week

Natalia Shakhova, Igor Semiletov, and collaborators (of University of Alaska’s International Arctic Research Centre and Russian Academy of Sciences in Vladivostok) published a paper last week in Science, titled ‘Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf’. They declared that the methane-rich, shallow East Siberian Arctic Shelf (ESAS), with a seafloor area of more than 772,200 square miles (three times the area of the Siberian wetlands, which are considered to be a chief source of atmospheric methane), is venting methane (the greenhouse gas) into the air and might trigger abrupt global warming.

After collecting over 5000 samples of seawater, the scientists measured the levels of dissolved methane at varying depths. High methane concentrations were observed in more than 80% of deep water and more than 50% of surface water samples, with most having concentrations more than eight times the normal amount in the Arctic Ocean. Analysing the air directly above the water surface and at higher elevations confirmed their findings. The team calculated that the region is releasing about 7 teragrams per annum (1 teragram is approximately 1.1 million tonnes), which is equal to the amount of methane emitted from the oceans (about 2% of the overall methane emissions to the atmosphere). As a result, more than 100 hotspots were located where methane is leaking from the sub-sea permafrost, which is believed to generally act as a lid to contain the methane reservoir.

When the earth becomes warm, warmer seawater enters the area. If and when the permafrost thaws, the stored frozen methane is released in two ways: Firstly, the stored organic material (ESAS, being shallow and averaging around 50 meters in depth, would have been submerged or terrestrial over the millennia) decomposes and gradually releases methane. Secondly, methane gas or methane hydrates could be released. Although methane usually oxidises into carbon dioxide before reaching the surface of deeper waters, it escapes to the atmosphere in the shallow ESAS.

The current average methane concentrations in the Arctic is around 1.85 ppm (which is the highest in 40,000 years), with much higher concentrations in ESAS- very alarming when considering that the Earth’s geological record indicates that atmospheric methane concentrations are between 0.3 to 0.4 ppm (during cold periods) and 0.6 to 0.7 ppm (during warm periods). As pointed out by Martin Heimann in his perspective in ‘Climate Change: How Stable Is the Methane Cycle?’ (in the same edition of Science), more warming in the Arctic, implies more destablisation of the permafrost, which implies more release of methane and the creation of ‘a positive feedback loop that amplifies global warming’.

Despite the current controversies in the field and the increased scepticisim about the effects of climate change, these findings might have heavy implications. A caveat is the vagueness over whether this is a new phenomenon or whether it is a constant natural phenomenon. What are the precise factors behind this? Will there be further larger release of methane? Will global warming accelerate this release? What would happen in such a scenario? Would it result in a rapid and devastating climate change, as predicted?

Additional reference:
http://www.uaf.edu/news/news/20100303192545.html

Paper of the Week: The link between snowfall increase in Antarctica and drought in southwest Western Australia

Tas van Ommen and Vin Morgan, of the Australian Antarctic Division, published a paper "Snowfall increase in coastal East Antarctica linked with southwest Western Australian drought" in Nature Geosciences. Turns out that this region of Australia has been facing a 40-year drought which was attributed to several factors, such as ‘natural variability, changes in land use, ocean temperatures and atmospheric circulation’. After evaluating the precipitation records of the two regions (East Antarctica and southwest Western Australia), the authors report an inverse correlation, surmising that the rain which should have fallen in Australia may have moved to Antarctica, resulting in heavy snowfall. What needs to be evaluated is whether this is purely due to anthropogenic climate change and whether the study can be substantiated by constructing similar correlations in other southern hemisphere nations which also has/had similar conditions of drought. van Ommen, T., & Morgan, V. (2010). Snowfall increase in coastal East Antarctica linked with southwest Western Australian drought, Nature Geoscience, 3 (4), 267-272