Climate change questions and answers
Anyone who has read Andrew Bolt, The Australian, or listened to any shock jocks such as Alan Jones recently would have been overwhelmed with the number of rabid claims that climate change is a hoax, a left-wing conspiracy theory, or that any change stopped over a decade ago. Sadly, this is the view held by our mainstream media and even more sadly, our new government. Neither seem interested in the facts.
Just over a week ago the the Commonwealth Scientific and Industrial Research Organisation (CSIRO) published Questions and Answers: climate change where they addressed some of the common questions raised about the changing climate and the science involved in studying it.
The media ignored it. The government ignored it. And as a result, you probably don’t know about it. After all, it was nothing more than a collection of facts: facts that contradicted what the media and government would want us to believe.
Below, I have reproduced a condensed version of the CSIRO’s discussion:
What is climate change? (natural & human-induced)
Human-induced climate change, represents a raft of new challenges for this generation and those to come, through increases in extreme weather events and other changes, such as sea-level rise and ocean acidification.
Climate change will be superimposed on natural climate variability, leading to a change in the frequency, intensity and duration of extreme events.
Climate risk profiles will be altered and adaptation will be necessary to manage these new risks. Adaptation includes new management practices, engineering solutions, improved technologies and behavioural change.
How has climate changed in the past?
In Australia, surface temperatures on the land have been recorded at many sites since the mid to late 19th century.
By 1910, Australia had a reliable network of thermometers and the data they produced have been extensively analysed by the Bureau of Meteorology and scientists at CSIRO, Australian universities and international research institutions.
This reveals that since 1910, Australia’s annual-average daily maximum temperatures have increased by 0.75°C and the overnight minima by more than 1.1°C.
Since the 1950s, each decade has been warmer than the one before. We’ve also experienced an increase in record hot days and a decrease in record cold days across the country.
Why do sea levels change?
Average global sea levels have been rising consistently since 1880 (the earliest available robust estimates) largely in response to increasing concentrations of greenhouse gases in the atmosphere and the consequent changes in the global climate.
There are two main processes behind long-term sea-level rises, which are a direct result of a warming climate.
Firstly, as the ocean has warmed the total volume of the ocean has increased through thermal expansion of water.
Secondly, water has been added to the oceans as a result of melting glaciers and ice sheets.
Sea levels began to rise in the 19th century and the rate of sea-level rise since the mid-19th century has been larger than the average rate during the previous two millennia.
Global-average sea levels are currently (between 1993 and 2010) rising at around 3.2mm per year, faster than during the 20th century as a whole.
How else are the oceans changing?
The heat content of the world’s oceans has increased during recent decades and accounts for more than 90 per cent of the total heat accumulated by the land, air and ocean since the 1970s.
This warming increases the volume of ocean waters and is a major contribution to sea-level rise. Ocean warming is continuing, especially in the top several hundred metres of the ocean.
Sea surface temperatures in the Australian region were very warm during 2010 and 2011, with temperatures in 2010 being the warmest on record. Sea surface temperatures averaged over the decades since 1900 have increased for every decade.
How is the composition of the atmosphere changing?
The concentration of CO2 in the atmosphere in 2011 was 391 parts per million (ppm) – much higher than the natural range of 170 to 300 ppm during the past 800 000 years.
Global CO2 emissions are mostly from fossil fuels (more than 85 per cent), land use change, mainly associated with tropical deforestation (less than 10 per cent), and cement production and other industrial processes (about 4 per cent).
Energy generation continues to climb and is dominated by fossil fuels – suggesting emissions will grow for some time yet.
How is climate likely to change in the future?
With greenhouse gas emissions continuing to increase, we expect the warming trend of the past century to accelerate throughout this century. We also expect changes to rainfall patterns and to the frequency of extreme weather events like cyclones and droughts.
Average temperatures across Australia are projected to rise by 0.4 to 1.8°C by 2030, compared with the climate of 1990. By 2070, warming is projected to be 1.0 to 2.5°C for a low emissions scenario, and 2.2 to 5.0°C for a high emissions scenario.
Australians will experience this warming through an increase in the number of hot days and warm nights and a decrease in cool days and cold nights.
Climate models show that there may be less rainfall in southern areas of Australia during winter and in southern and eastern areas during spring. Wet years are likely to become less frequent and dry years and droughts more frequent.
Climate models suggest that rainfall near the equator will increase globally, but it’s not clear how rainfall may change in northern Australia.
Australia will also experience climate-related changes to extreme weather events. In most areas of the country, intense rainfall events will become more extreme.
Fire-weather risk is also likely to increase and fire seasons will be longer. And although it is likely that there will be fewer tropical cyclones in the Australian region, the proportion of intense cyclones may increase.
What is extreme weather and how is it changing?
The natural climate variability that underlies all extreme weather events is now influenced and altered by the effect of human-induced warming of the climate system.
Future climate change impacts will be experienced mostly through extreme events rather than gradual changes in mean temperature or rainfall.
Heatwaves, floods, fires and southern Australian droughts are expected to become more intense and more frequent. Frosts, snow and cyclones are expected to occur less often.
Extreme events and natural disasters place a huge burden on individuals, communities, industry and the government and have an enormous impact on Australia’s economy, social fabric and environment.
What are the impacts of climate change?
Australia is expected to experience an increase in extremely high temperatures, extreme fire weather, extreme rainfall events, tropical cyclone intensity, extreme sea levels, and droughts in southern areas.
A decrease in the frequency of extremely cold temperatures is expected, along with fewer tropical cyclones.
These changes will pose significant challenges for disaster risk management, water and food security, ecosystems, forestry, buildings, transport, energy, health and tourism.
For example, many animal and plant species may decline or become extinct, water resources are expected to decline in southern Australia, agricultural zones are likely to shift, coastal erosion and inundation is expected to occur more often, energy demand is likely to increase, snow cover will decline and heat-related deaths may rise.
Is the science settled?
In climate change science, robust findings include:
- clear evidence for global warming and sea level rise over the past century
- changes observed in many physical and biological systems are consistent with warming
- due to the uptake of anthropogenic CO2 since 1750, ocean acidity has increased
- most of the global average warming over the past 50 years is very likely due to anthropogenic greenhouse gas increases
- global greenhouse gas emissions will continue to grow over the next few decades, leading to further climate change
- due to the time scales associated with climate processes and feedbacks, anthropogenic warming and sea level rise would continue for centuries even if greenhouse gas emissions were to be reduced sufficiently for atmospheric concentrations to stabilise
- increased frequencies and intensities of some extreme weather events are very likely
- systems and sectors at greatest risk are ecosystems, low-lying coasts, water resources in some regions, tropical agriculture, and health in areas with low adaptive capacity
- the regions at greatest risk are the Arctic, Africa, small islands and Asian and African mega-deltas. Within other regions (even regions with high incomes) some people, areas and activities can be particularly at risk
- unmitigated climate change would, in the long term, be likely to exceed the capacity of natural, managed and human systems to adapt
- many impacts can be reduced, delayed or avoided by mitigation (net emission reductions). Mitigation efforts and investments over the next two to three decades will have a large impact on opportunities to achieve lower greenhouse gas stabilisation levels.
It is incredible that this information has been unreported and I would assume, largely ignored. Instead, we will continue to be inundated with claims that rabid claims that “climate change is a hoax, a left-wing conspiracy theory, or that any change stopped over a decade ago.”
It is an act of gross negligence that our media fails to accurately report the reality of climate change. It is also an act of gross negligence that our new government fails to embrace the challenges.
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