CLIMATE CHANGE BASICS
Climate change is the biggest threat facing humanity. But what is it and what is causing it?
The term ‘climate change’ refers to the trends in climate patterns - including rising global temperature, as well as changes in rainfall and wind patterns - attributable to human activity that alters the composition of the atmosphere. While climate has changed in the past, and it is influenced by many factors, human activity is the biggest driver of the rapid disruption observed over the past century.
Globally, nine of the ten hottest years on record have occurred since 2005, with the last five years being the hottest ever recorded. The trend is clear and is occurring at an unprecedented speed. Human society has grown and flourished during a long period of stable climate. We depend on that climatic equilibrium - so what has disrupted it?
Greenhouse gases (including carbon dioxide and methane) are naturally present in our atmosphere and act as a ‘blanket’ around the Earth, maintaining a relatively stable temperature. But since the beginning of the industrial revolution, humans have been digging up and burning ever increasing quantities of fossil fuels (coal, oil and natural gas), releasing more and more greenhouse gases into the atmosphere, trapping more and more heat. Deforestation has also had a major impact. The world’s forests act as carbon sinks, but when they are cut down or burnt, they release greenhouse gases into the atmosphere. Pre-industrial levels of atmospheric carbon dioxide were around 260-270ppm; it is now over 400ppm.
Most of the extra trapped heat is absorbed by the oceans. Global average air temperature has increased by over 1 degree C since pre-industrial times. This might sound like a small increase, but this ‘small’ increase is already causing more extreme weather events, rising sea levels, coral bleaching, changes in distribution of species and disease, as well as other significant impacts. If business as usual continues, we are on track to see global average temperatures increasing by over 4 degrees C by the end of this century, which will be catastrophic for humanity and many other species.
If humans are causing the problem, we can also choose to act to solve it. We have a responsibility to act. We need to act now and act fast, before dangerous tipping points are reached. Read more about the solutions here. See links for more on climate science.
Read on below to find out how this impacts us on the Coffs Coast.
The term ‘climate change’ refers to the trends in climate patterns - including rising global temperature, as well as changes in rainfall and wind patterns - attributable to human activity that alters the composition of the atmosphere. While climate has changed in the past, and it is influenced by many factors, human activity is the biggest driver of the rapid disruption observed over the past century.
Globally, nine of the ten hottest years on record have occurred since 2005, with the last five years being the hottest ever recorded. The trend is clear and is occurring at an unprecedented speed. Human society has grown and flourished during a long period of stable climate. We depend on that climatic equilibrium - so what has disrupted it?
Greenhouse gases (including carbon dioxide and methane) are naturally present in our atmosphere and act as a ‘blanket’ around the Earth, maintaining a relatively stable temperature. But since the beginning of the industrial revolution, humans have been digging up and burning ever increasing quantities of fossil fuels (coal, oil and natural gas), releasing more and more greenhouse gases into the atmosphere, trapping more and more heat. Deforestation has also had a major impact. The world’s forests act as carbon sinks, but when they are cut down or burnt, they release greenhouse gases into the atmosphere. Pre-industrial levels of atmospheric carbon dioxide were around 260-270ppm; it is now over 400ppm.
Most of the extra trapped heat is absorbed by the oceans. Global average air temperature has increased by over 1 degree C since pre-industrial times. This might sound like a small increase, but this ‘small’ increase is already causing more extreme weather events, rising sea levels, coral bleaching, changes in distribution of species and disease, as well as other significant impacts. If business as usual continues, we are on track to see global average temperatures increasing by over 4 degrees C by the end of this century, which will be catastrophic for humanity and many other species.
If humans are causing the problem, we can also choose to act to solve it. We have a responsibility to act. We need to act now and act fast, before dangerous tipping points are reached. Read more about the solutions here. See links for more on climate science.
Read on below to find out how this impacts us on the Coffs Coast.
WHAT DOES CLIMATE CHANGE MEAN FOR THE COFFS COAST?
We all the love the climate on the Coffs Coast! But will it always be like this? Climate change is already impacting the Coffs Coast environment, economy and community, and these impacts will grow unless the root problem is addressed quickly. Impacts include:
HEAT: Average temperatures on the NSW North Coast are predicted to rise by 2 degrees C by 2070, with more very hot days, more and longer heat waves, less cold days and reduced chance of frosts. Heatwaves can cause health problems (see 'health' below), restrict work capacity, damage infrastructure such as electricity distribution and transport systems. Heat stress can also impact crops and livestock (see 'agriculture' below) and trigger mass deaths of heat sensitive species such as flying foxes and birds.
RAINFALL CHANGES: Rainfall on the NSW North Coast is expected to be reduced in winter, but increase at other times of the year. Heavy rain events and increasingly severe storms and flooding may occur in the warmer seasons. Warmer ocean temperatures may enable cyclones to maintain their intensity as they move south along the coast. On the other hand, droughts will be more severe.
For more detailed climate projections for NSW North Coast see here.
SEA LEVEL RISE: Sea levels are rising because of thermal expansion and melting land ice. There has already been a rise of about 20cm since pre-industrial times. The Intergovernmental Panel on Climate Change (IPCC) predicts a likely sea level rise of 91cm by 2100, though up to 2 metres is possible. The Coffs Coast will see an increase in coastal inundation, significantly impacting private property, infrastructure, beaches, with disruptions to the tourism industry and the economy more generally. In NSW there are 700-1200 commercial buildings, up to 68,000 residential buildings, plus around $1 billion worth of rail exposed to sea level rise. See the Climate Council's Coastal Flooding report for more details.
Coffs Harbour City Council are planning for these changes. See their maps showing areas at risk of inundation here.
BUSHFIRES: Bushfires have always occurred, but climate change is increasing fire danger weather and thus the risk of fires. The fire season is starting earlier and lasting longer. In 2013, the official fire season in Coffs started on 1st August – that’s still winter! The total economic costs of NSW bushfires in 2014 are expected to be $43 million. By about 2050, this cost is expected to triple. By 2030, it is estimated that the number of professional firefighters will need to double. For more information, see Climate Council reports here or the Australian Firefighters Climate Alliance.
HEALTH: In May 2009, The Lancet pronounced climate change "the biggest global health threat of the 21st century". More heatwaves increase the risk of heat-related illnesses and death, particularly in the elderly. In the last 100 years heatwaves have caused more deaths in Australia than any other natural hazard. Climate change is also predicted to increase the distribution of mosquito borne diseases. There are already reports of diseases such as Ross River fever becoming more common on the Coffs Coast. See the Climate Council's report on climate and health in Australia here and check out the Climate and Health Alliance. The mining and burning of coal also impacts on health directly through air pollution - see here.
AGRICULTURE: Australian agriculture is reliant on predictable temperature and rainfall to maintain high productivity and quality. Heat stress can reduce crop yields and decrease livestock productivity, particularly in the dairy industry. Intense heat can exacerbate droughts and vice versa. Australia's food security is at risk from climate change. For more on climate change impacts on agriculture, see the Appetite for Change report.
OCEAN LIFE: In March 2016, reports of coral bleaching in the Solitary Island Marine Park shocked many of us here on the Coffs Coast. Not only is climate change impacting on marine life through warmer ocean temperatures, changing winds and currents and extreme events like cyclones, but a related process is also changing the chemistry of the Earth's oceans. Ocean acidification occurs as atmospheric carbon dioxide dissolves in seawater, creating carbonic acid and limiting the availability of carbonate ions, which marine organisms need to build their shells and exoskeletons. The distribution, abundance and breeding cycles of many ocean species are under threat, as are the seaside communities that rely on them. The Solitary Islands Marine Park is a very special, diverse marine environment, unique because it is the meeting place of warm and cool currents. It is home to a number of threatened and endemic species, such as the wide-band anemone fish. While many fish species have been observed to be shifting south along East Coast Australia with warming oceans, this is not possible for all species with specific habitat requirements. Rising sea levels also impact on appropriate habitat, for example rocky intertidal zones.
Some of the above information is adapted from:
The Climate Council of Australia’s publication ‘What does climate change mean for your local area? The Federal Electorate of Cowper’, available here.
NSW Office of Environment and Heritage Climate Projections, available here.
HEAT: Average temperatures on the NSW North Coast are predicted to rise by 2 degrees C by 2070, with more very hot days, more and longer heat waves, less cold days and reduced chance of frosts. Heatwaves can cause health problems (see 'health' below), restrict work capacity, damage infrastructure such as electricity distribution and transport systems. Heat stress can also impact crops and livestock (see 'agriculture' below) and trigger mass deaths of heat sensitive species such as flying foxes and birds.
RAINFALL CHANGES: Rainfall on the NSW North Coast is expected to be reduced in winter, but increase at other times of the year. Heavy rain events and increasingly severe storms and flooding may occur in the warmer seasons. Warmer ocean temperatures may enable cyclones to maintain their intensity as they move south along the coast. On the other hand, droughts will be more severe.
For more detailed climate projections for NSW North Coast see here.
SEA LEVEL RISE: Sea levels are rising because of thermal expansion and melting land ice. There has already been a rise of about 20cm since pre-industrial times. The Intergovernmental Panel on Climate Change (IPCC) predicts a likely sea level rise of 91cm by 2100, though up to 2 metres is possible. The Coffs Coast will see an increase in coastal inundation, significantly impacting private property, infrastructure, beaches, with disruptions to the tourism industry and the economy more generally. In NSW there are 700-1200 commercial buildings, up to 68,000 residential buildings, plus around $1 billion worth of rail exposed to sea level rise. See the Climate Council's Coastal Flooding report for more details.
Coffs Harbour City Council are planning for these changes. See their maps showing areas at risk of inundation here.
BUSHFIRES: Bushfires have always occurred, but climate change is increasing fire danger weather and thus the risk of fires. The fire season is starting earlier and lasting longer. In 2013, the official fire season in Coffs started on 1st August – that’s still winter! The total economic costs of NSW bushfires in 2014 are expected to be $43 million. By about 2050, this cost is expected to triple. By 2030, it is estimated that the number of professional firefighters will need to double. For more information, see Climate Council reports here or the Australian Firefighters Climate Alliance.
HEALTH: In May 2009, The Lancet pronounced climate change "the biggest global health threat of the 21st century". More heatwaves increase the risk of heat-related illnesses and death, particularly in the elderly. In the last 100 years heatwaves have caused more deaths in Australia than any other natural hazard. Climate change is also predicted to increase the distribution of mosquito borne diseases. There are already reports of diseases such as Ross River fever becoming more common on the Coffs Coast. See the Climate Council's report on climate and health in Australia here and check out the Climate and Health Alliance. The mining and burning of coal also impacts on health directly through air pollution - see here.
AGRICULTURE: Australian agriculture is reliant on predictable temperature and rainfall to maintain high productivity and quality. Heat stress can reduce crop yields and decrease livestock productivity, particularly in the dairy industry. Intense heat can exacerbate droughts and vice versa. Australia's food security is at risk from climate change. For more on climate change impacts on agriculture, see the Appetite for Change report.
OCEAN LIFE: In March 2016, reports of coral bleaching in the Solitary Island Marine Park shocked many of us here on the Coffs Coast. Not only is climate change impacting on marine life through warmer ocean temperatures, changing winds and currents and extreme events like cyclones, but a related process is also changing the chemistry of the Earth's oceans. Ocean acidification occurs as atmospheric carbon dioxide dissolves in seawater, creating carbonic acid and limiting the availability of carbonate ions, which marine organisms need to build their shells and exoskeletons. The distribution, abundance and breeding cycles of many ocean species are under threat, as are the seaside communities that rely on them. The Solitary Islands Marine Park is a very special, diverse marine environment, unique because it is the meeting place of warm and cool currents. It is home to a number of threatened and endemic species, such as the wide-band anemone fish. While many fish species have been observed to be shifting south along East Coast Australia with warming oceans, this is not possible for all species with specific habitat requirements. Rising sea levels also impact on appropriate habitat, for example rocky intertidal zones.
Some of the above information is adapted from:
The Climate Council of Australia’s publication ‘What does climate change mean for your local area? The Federal Electorate of Cowper’, available here.
NSW Office of Environment and Heritage Climate Projections, available here.