Early morning on 26 June PowerFM interviewed me for a few minutes in their news segment about the heat wave that south Pakistan was experiencing. For five days in a row temperatures reached low- to mid-40 degrees Celsius, leading to the deaths of over 2 000 people, and causing the prime minister of Pakistan to declare a state of emergency.
This has not been the first recent heat wave leading to such high deaths, and will highly likely not be the last:
- In 2003 a heat wave hit Europe that killed over 50 000 people;
- The 2010 Russian heat wave lead to the deaths of around 56 000 people; and
- In May this year nearly 2 500 people died in India when temperatures reached above 45 degrees Celsius.
(Source: Dave Granlund)
Whilst heat waves are already occurring more frequently in Europe, Asia and Australia, climate change is expected to lead to more hot days and warmer nights, and higher temperatures over nearly all land areas. The latest assessment report of the Intergovernmental Panel on Climate Change (IPCC 2014:19) found that it is “likely that human influence has more than doubled the probability of occurrence of heat waves in some locations”. Another study (Christidis et al 2015) found that human-caused climate change makes it ten times more likely than a decade ago for heat waves such as the 2003 one to occur in Europe again. Not only will heat waves occur more frequently in Europe, Asia and Australia due to climate change, but it is also expected to last longer and be more severe (Herring et al 214; Steffen et al 2014).
Like the radio interviewer (Lawrence Tlhabane), you might wonder how heat waves are related to climate change? Think of the striker of one of the top soccer teams. (For my niece I would have to make it Messi or Neymar). This player already scores many goals due to his talent and training; should he take performance-enhancing drugs, he is very likely to be even more on target and become immortalised as the best striker ever!
(Source: FC Barcelona)
Global warming is the earth on performance-enhancing drugs; as the average temperature goes up, we’re more likely to experience frequent hotter days, and some areas are more likely to experience more heat waves. Thus, whilst it is not possible to say that a specific extreme weather event, such as the heat wave in Pakistan, is attributable to climate change, the scientific consensus is that extreme weather events (such as heat waves, floods and droughts) are more likely to occur with more intensity, due to climate change. Thus, it is likely for heat waves to occur more often, be higher in temperature and last longer.
What are some of the impacts of heat waves occurring more frequent and being more intense?
- The most immediate impact of a heat wave is morbidity (illness) and premature mortality (death), as we have seen in Pakistan. We must remember our bodies’ normal temperature is 37-38C. Once it heats up to 39-40C, our muscles slow down and fatigue sets in. At 40-41C heat exhaustion and heatstroke is likely, and above 41C our bodies start to shut down, with risk of multiple organ failure (see BBC 2013). “In America on average over the last 30 years, excessive heat accounts for more reported deaths annually than hurricanes, floods, tornadoes, and lightning combined.” (Adams). Various studies (quoted in Vescovi et al 2005) found the “strongest correlation factors between impacts of high temperature events on mortality and morbidity, and social factors include age (Besancenot 2002; Diaz et al 2002), poverty (INSERM 2003), social isolation (Besancenot 2002), and education level (Ballester et al. 1997). And a report released the end of June by The Lancet (Watts et al 2015) diagnoses climate change as ‘a medical emergency’, due to its health impacts.
- Increased morbidity and mortality put pressure on existing health infrastructure. In Pakistan, for example, 14 000 people were seeking help at hospitals, and the mortuaries ran short of space (The New York Times 25 June 2015; News24 25 June 2015). In such a crisis it is likely that emergency staff will be overwhelmed and overworked by the scale of the crisis, also because such staff will themselves experience heat stress.
- Current vulnerable social groups are more at risk than others to heat waves; for example, older people and children, those living alone, those with pre-existing diseases (especially cardiovascular and respiratory illnesses), those who are immobile, those suffering from mental illness, and the homeless and urban poor (due to the urban heat island effect). Such vulnerable people have limited adaptive capacity to deal with heat waves, and other extreme weather events.
- Some argue that there is an association between heat waves / hot weather and social disturbances, unrest and crime – this remains debatable, and should rather be seen as speculative rather than definitive (see Anderson 1989; Anderson et al 1997; Cohn 1990, 1993; Field 1992; Rotton and Cohn 2000a, 2000b). In Karachi in Pakistan we saw sporadic protests blaming deaths on the government and the main power utility, after electricity blackouts (The Independent 25 June 2015; Time 24 June 2015).
- But heat waves are likely to affect electricity supply. Not only is power outages more likely due to heat causing transmission lines to sag, but the increased demand for electricity to keep people cool through air conditioners further increase the likelihood of blackouts.
- Another key service affected by heat waves is water services and infrastructure. Increased demand for water, combined with likely electricity outages, can lead to a crisis in water availability. Furthermore, the rise in water temperatures will reduce water quality, not only affecting human consumption and health, and increased cost to clean water, but fish populations and other organisms in the water ecosystem will also be affected.
- Within the agricultural sector livestock may be affected, with, for example, milk production of cows being reduced; and wheat, maize and other plant growth being affected if a heat wave occurs at key developmental stages. Reduced harvests with have a knock-on effect on food security. With veldfires more likely in heat waves (refs), crops and grazing can be affected.
- A warmer world, on average, means a more humid world (Huber & Gulledge 2011). In higher humidity our sweat don’t evaporate, and we feel hot and sweaty, thus increasing our discomfort. [Remember, in a heat wave there is little respite – the normal trend of cooler nights does not happen, combined with consecutive hot days.] Combined with labour power morbidity, reduced production is likely. In Pakistan, for example, an emergency was declared, with schools and government offices closed.
- And, heat waves can lead to increased economic costs in transportation. In Pakistan, for example, road infrastructure was damaged. Railway tracks might bend, and mechanical failure in cars is likely due to stress on car cooling systems.
(Source: The Huffington Post – from Hindustan Times)
In increased likelihood of occurrences of extreme weather events – such as heat waves, floods and drought – means that we have to look at mitigation. Two recent court judgements – one in the US and the other in the Netherlands – highlight this. In the US in King County a court asked the Washington state Department of Ecology to reconsider a petition by eight youth for state-wide reductions in carbon-dioxide emissions (Western Environmental Law Center 2015). And the end of June a Dutch court ordered the Dutch government to cut greenhouse emission by 2010 with 25% compared to 1990 levels, in order to protect its people from global warming (Nature 24 June 2015). But mitigation is not enough; we need adaptation as well. And adaptation requires that we reconsider the values that underpin our living in the age of the Anthropocene. In a recent research article Gina Ziervogel and colleagues (2014:615) argued that “Climate change adaptation requires forward-looking decision-making that marries scientific diagnoses and technical innovation with social organisation and political debate around competing value systems.” And in June Pope Francis wrote in an encyclical on the environment that “Climate change is a global problem with grave implications: environmental, social, economic, political and for the distribution of goods.” Indeed, climate change (and extreme weather events such as heat waves) is not only an environmental problem, but also a political, development, economic and social challenge.
List of references
Adams CR Impacts of temperature extremes. Cooperative Institute for Research in the Atmosphere, Colorado State University:
BBC (18 July) 2013 What happens to the body in extreme heat?
Christidis N, Jones GS & Stott PA 2015 Dramatically increasing chance of extremely hot summers since the 2003 European heatwave. Nature Climate Change 5: 46–50. doi:10.1038/nclimate2468
Herring SC, Hoerling MP, Peterson TC & Stott PA (eds) 2014 Explaining extreme events of 2013 from a climate perspective. Special Supplement to the Bulletin of the American Meteorological Society 95(9)
Huber D & Gulledge J 2011 Extreme weather and climate change: Understanding the link and managing the risk. Centre for Climate and Energy Solutions.
IPCC 2014 Climate change 2013: The physical science basis (Working Group 1 contribution to the Fifth Assessment Report of the IPCC). New York: Cambridge University Press
Nature 24 June 2015 Landmark court ruling tells Dutch government to do more on climate change
News24 25 June 2015 Pakistan morgues run out of space as heat wave kills 1 000
Steffen W, Hughes L & Perkins S 2014 Heat waves: Hotter, longer and more often. Climate Council of Australia.
The Independent 25 June 2015 Karachi heat wave: Death toll tops 1 000 as government and electricity company trade blame
The New York Times 25 June 2015 Death toll from heat wave in Karachi, Pakistan, hits 1000
Vescovi L, Rebetez M & Rong F 2005 Assessing public health risk due to extremely high temperature events: Climate and social parameters. Climate Research 30: 71-78
Watts N et al 2015 Health and climate change: Policy responses to protect public health. The Lancet
Western Environmental Law Center 2015 Washington State youth win unprecedented decision in their climate change lawsuit – Press release on 24 June
Ziervogel G 2014 Climate change impacts and adaptation in South Africa. WIREs Climate Change 5: 605-620. doi: 10.1002/wcc.295