Showing posts with label Environment - Climate Change - Other Impacts. Show all posts
Showing posts with label Environment - Climate Change - Other Impacts. Show all posts

Saturday 25 January 2020

Australia since 1970 - less water and increasing droughts


Time-based data evaluation and mapping by the Bureau of Meteorology starkly demonstrates the historical pattern of less rainfall over the Eastern half of the Australian continent which has occurred over the past 40 years. The Eastern half of the continent, comprising the states of  Victoria, New South Wales and Queensland, produces most of the agricultural outputs whereas the Western half of the continent is semi-arid, arid to desert and cannot support food production. The impact of less rainfall will be continue to be an acute problem and one which requires faster adaptation than is currently the case. 

Sunday 31 March 2019

The Reserve Bank and climate change


The March 2019 speech by the Deputy Governor of the Reserve Bank of Australia (RBA), Guy Debelle on climate change and the economy was something of a watershed moment for many commentators in the media. Here was a senior official of Australia's central bank acknowledging the serious impact that climate change could and almost certainly will have on Australia's economy in future years in stark contrast to negligible statements by the Australian Government.

Debelle's address to a public forum hosted by the Centre for Policy Development in Sydney follows closely similar comments by other key federal regulators, the Australian Prudential Regulation Authority (APRA) and the Australian Securities and Investments Commission (ASIC).

What made Debelle's address so essential is that it was framed within the context of  economic models and monetary policy - the key instruments which the RBA uses to influence the Australian economy.  According to the RBA, when thinking about weather its important to see it in terms of a trend rather than cycles: "The impact of a trend is ongoing, whereas a cycle is temporary".  Frequency of climate events needs to be considered and how the economy adapts to increasing sudden shocks which affect demand and supply.

RBA has joined the Network for Greening the Financial System (NGFS) which is a group of central banks looking at climate issues and impact.

The speech can be accessed at the link below:
Address by the RBA Deputy Governor on climate change  

Saturday 4 March 2017

Mosquitoes - the threat expands with a warmer climate

The Summer warnings in NSW in early 2017 of the potential for an outbreak of Ross River Fever again underscores the risks posed by pathogens carried by mosquitoes who readily benefit from warmer and moister weather. Ross River Fever was first isolated in the Ross River region near Townsville, Queensland, over half a century ago. Since that time the condition has been identified as being fairly endemic across Australia in warmer regions and in near neighbouring countries such as Papua New Guinea. During periods of colder temperatures the risk is minimised as the carrier mosquitoes are limited in their breeding cycle however with milder temperatures, longer Summers and intense periods of storm activity with higher humidity, the mosquito's geographic range is expanded. Matched with a longer breeding season due to these same conditions, the propensity for greater disease outbreaks is very real.

Across the planet similar concerns are being expressed in relation to various species of mosquito which are vectors for a range of dangerous pathogens either endangering life or causing serious debilitating effects.  Only a handful of the known 3,500 species of mosquito feed on human blood and these are only female as male mosquitoes live off plants. This handful are, nonetheless, devastating in impact for diseases such as malaria alone kills over 400,000 people a year. The chief culprits are listed on the table below: 

Mosquito species
Pathogens carried
Aedes aegypti
Found in cities, this species feeds almost exclusively from human blood.

Zika virus
Chikungunya
Yellow Fever
Dengue Fever
Aedes albopictus
An aggressive, adaptable species which can colonise the habitats of other mosquitoes.

Zika virus
Chikungunya
Dengue fever
Haemagogus
A major carrier of yellow fever, they can be identified by their metallic sheen.


Yellow Fever
Anopheles
This species has long front feelers and is the only genus that transmits malaria.


Malaria
Lymphatic filariasis
Culex quinquefasciatus
Common around the world, this species are night feeders and lay their eggs in dirty water.


Lymphatic filariasis
West Nile fever


Zika virus has become the most recent addition to the list of dangerous pathogens in North and South  America but it is not alone. In Brazil, Mayaro, a monkey virus is now infecting people in the North West of that country as a result of mosquito transmission. As much of the debate on climate change focusses on energy generation and adaptation technology and design, an equal amount of effort is needed on examining the public health ramifications across a range of impacts. Ultimately these may have a much earlier effect.

Saturday 12 March 2016

Climate change and mosquito borne pathogens and parasites

Over recent months, much of the media commentary has been focussed on the Zika virus (transmitted by mosquito bites) and its potential to affect the Olympic Games to be held in Rio de Janeiro between 5th and 21st August 2016.  The increasing risk of serious vector-borne disease is much greater that most periodic media reports would suggest and more so with the increasing impact of climate change. The main risks, which to a limited extent, are already realised involve pathogens and parasites such as Malaria and Dengue fever (from Mosquitoes), Sandfly fever and Leishmaniasis (from Sand Flies) and Lyme Disease and Encephalitis (from Ticks) all of which have the potential to have an expanded geographic range due to warmer weather. The increased temperatures enable the transmitting insects to travel further afield than is currently the case moving into areas that previously were free of disease. Dengue fever, for example, is found in a band between the Tropic of Cancer and the Tropic of Capricorn and not fully across the entire region. Warmer weather will enable this range to expand in both North and South latitudes. Dengue cases have already been increasing from 0.5m in 1990 to almost 2.7M by 2013. The projected increase in future years is 12-18% by 2030 and vaccines are only in the very early stages of developmnent. Malaria has now been detected in higher altitude regions of Papua New Guina where there was no previous exposure. Public health authorities have only just started to grasp the scale of this on-the-horizon issue and the threat to health may yet prove to have a significant impact on outdoor living activities.

Sunday 8 November 2015

Climate Change and Health - report from The Lancet Climate Change Commission

The Greenhouse Gas Exchange and effects on health
While much of the attention in the debate on climate change has been focussed on greenhouse gases, notably CO2 emissions, ice melt, sea level rise and the increased magnitude of adverse and/or extreme weather conditions, an equally critical impact is on human health.  The Lancet in the United Kingdom established the Lancet Commission on Health and Climate Change which has published a series of periodic in-depth policy and analysis reports focussing on the effect of climate change on health, the latest of which in 2015 has reinforced the need for concerted Government level initiatives.

As noted by the Commission, the principal pathways linking climate change to health outcomes are categorised as direct or indirect mechanisms which interact with social dynamics to produce health outcomes. The direct risks are extreme weather  events and resultant storms, floods, droughts or heatwaves. The indirect risks are mediated through changes in the biosphere (such as the burden of disease, distribution of disease vectors or food availability) while others occur through social processes (such as migration and conflict) In summary, therefore there are three pillars which interact with each other influenced by factors such as changes in land use, crop yield, ecosystems, global development and demographic processes (shown in the diagram below). 
The 3 Pillars concept of interaction
An example of such interconnectivity, can be seen with rising temperatures and changes in precipitation patterns altering the viable  distribution of disease vectors such as mosquitoes carrying dengue and malaria. This is already the case with malaria and dengue reaching higher altitude highland regions which were previously unaffected. Changing weather patterns have a direct correlation to availability of non contaminated drinking water - both storms and droughts increase the risk of contamination and provide the conditions of bacterial growth. Ground level ozone (GLO) and particulate air pollutants are also strongly affected by climate change with increases in exposure to both being a known hazard.

The report can be accessed at the link below:
Climate Commission Report - Climate Change and Health

Sunday 1 March 2015

Aircraft, contrails and climate change - options for change

White contrails often seen streaking across the sky are the water vapour in hot aircraft exhaust which freezes when it meets cold moist air in the atmosphere. These contrails can and do form into wispy cirrus clouds which trap heat and thus contribute to global warming and more so that the actual carbon emissions from the aircraft themselves. Are there options to address this effect ?

Noting that there are few viable technological options for reducing contrails, one proposal canvassed by researchers, Irvine, Hoskins and Shine, is to consider re-routing aircraft to control emissions depending on the weather. In one transit model posited by the researchers, a 13.7 mile detour for a transatlantic flight eliminated a contrail 62 miles long and the clouds which would have formed from it.

Whether this method can have a practical application remains to be seen. The need for considering relatively cost-effective options with a positive environmental result remains paramount.

The original research article can be found at the link below:

Saturday 16 November 2013

Climate Change Insight: more carbon dioxide = more plants

Savannah vegetation
One of the many contradictions in climate science is understanding the impact of higher levels of carbon dioxide CO2 in the atmosphere on plant growth. The central thesis contends that increased levels of CO2, warmer temperatures and the creation of wetter climes in some areas of the globe should produce higher levels of vegetation through the stimulation of photosynthesis. One of the tests for this theory has been undertaken by Australia's CSIRO which has been monitoring the edges of many arid areas in Australia, Southern Africa, the Southwest of the United States, North Africa, the Middle East and Central Asia. The results of the monitoring process has found that the amounts of vegetation per unit of rainfall actually rose by 11 per cent rather than remaining constant. In short, the increase in vegetation occured where the only input which had altered was the corresponding increase in CO2 levels. 

This increase does not apply to all the dry regions of the world and in many cases, there will be no change at all due to the scarcity of water which will become more extreme in arid mid latitude geographical locations.The long term effects of increased vegetation in terms of potentially locking down CO2 emissions are unknown although current atmospheric greenhouse gas increases are considered to be too high to be matched by plant growth.

Friday 4 October 2013

Climate Change Insight: How the Earth's tilt is affected

As most high school students would know (and the rest of us remember), the Earth spins, or more accurately, it wobbles on an axis which in turn causes the magnetic poles to shift slowly. The Earth's rotational axis and its rate of spin are influenced by the fact that the planet is not a perfect sphere but rather has a changing surface caused by plate tectonics, movement of mass such as oceans due to the weather and erosion of solid structures. The drift has generally been around 6 centimetres a year with the poles moving in a constant direction however in 2005 this suddenly both changed and accelerated. The drift switch was a surprise and researchers at the University of Texas using the GRACE satellites (or Gravity Recovery And Climate Experiment) have found the answer. 

Warming temperatures have led to an extraordinary loss of mass in glaciers in Greenland, Antarctica and large mountain ranges in the order of 600 gigatonnes a year. The redistribution of water from ice surfaces to the oceans accounts for almost the entire change in the Earth's polar tilt since 2005 and its acceleration.

Sunday 15 September 2013

Forests and Weather: Can't see the clouds for the trees ?

Environmental scientists have been able to correlate rainfall and temperature patterns with large forest growth for many years however the exact role of forests in the regulation of temperature as well as with the formation of water molecules remains a matter of conjecture. One proposition, of several possible theories, which has garnered strong support  originates from the University of Helsinki and formulates a possible feedback loop exists from trees to aerosol particles. Many plants produce a group of chemicals termed 'Terpenes'. Terpenes are familiar to most people as the smell of pine forests and are the main constituents of turpentine. As terpene molecules are highly volatile the process of oxidisation is theorised to make them less volatile leading to condensation into aerosol particles which have a cooling effect. If this is the case, then the steady deforestation of the planet, through logging/land clearing, weather patterns and outbreaks of disease in trees portents another negative impact on planetary-wide temperature and rainfall patterns. 

Sunday 3 February 2013

Coffee and Global Warming - the risk is out there

While most of the effects of global warming and climate change focus on rising seas, higher temperatures, ocean salinity, super storms and so on, a number of other impacts which will affect human population are often overlooked or sparsely presented. One aspect of climate change which will cause concern is the world-wide reduction of coffee supplies. Coffee is grown in over 70 countries around the world, supports over 26 million farmers and generates exports of over $15 billion a year mainly for developing countries. The coffee industry is reliant for two thirds of its production from just one species, Coffea arabica, which originated from Ethiopia over four centuries ago. C. arabica requires temperatures between 180C and 210C with a reasonable mix of dry weather (for buds to grow) and wet weather (for flowering). From 230C upwards the plant exhibits stress and produces poorer quality beans and above 300C the plant develops tumours and loses its leaves.

Between 2009 and 2012 coffee yields fell to a 35 year low due to extraordinary rains and then unseasonable dryness - a portent of events to come. According to the IPCC's most optimistic projections, by 2080 around 65% of current geographic locations for wild coffee will be unsuitable and this rises up to 99.7% at the worst case scenario. Coffee production will fall well before 2080 however and within the next twenty years. Matched with the changing temperature is the expanded proliferation of the coffee weevil,  Hypothenemus hampei which has spread to every coffee-producing country with the exceptions of Nepal and China. This small borer attackes the coffee beans and requires only a small temperature rise to increase the number of generations born in any cycle. On current trends and with estimates of warming up to 4 degrees Celsius higher, up to ten generations of borer could occur each year.

The only option is to find a substitute for C arabica form the 125 other species of coffee which might tolerate global warming and be drinkable. As yet, none have been positively proven although coffea canephora (also known as Robusta) shows promise.

 

Friday 3 February 2012

Where fact is stronger than fiction: ice age phenomena

Science fiction enthusiasts , environmentalists and general movie buffs will be familiar with the 2004 film 'The Day After Tomorrow" where the Earth particularly the Northern Hemisphere is faced with another ice age in a very short time frame of only weeks whereas conventional theory and models tended to view changes as taking decades to occur. Recent research from ancient lake drillings at Lake Monreagh in Ireland have indicated that the Younger Dryas mini Ice Age which took place 12,800 years ago took only months, at most a year, to occur. 

This ice age wihich covered the Northern  Hemisphere was caused by a slowdown in the Gulf stream and lasted approximately 1,300 years with a correspondingly devastating impact on early human societies and culture which existed in the region at that time. Until recently it was considered, based on ice core samples from Greenland, that the mini ice age took at least a deacde to evolve but this has now sharply contradicted by the new findings. The conclusion to draw from this research is simply that climate change phenomena can occur much more quickly that first thought and simply delaying essential decisions does little to reduce risk.