CLIMATE CHANGE IS REAL

 

Global warming is caused by a build-up of carbon dioxide and other greenhouse gases in the atmosphere. These gases trap heat from the sun, warming the planet. Current levels of greenhouses gases (carbon dioxide, methane and nitrous oxide) in the atmosphere are higher than at any point over the past 800,000 years.

 

The UN Intergovernmental Panel on Climate Change (see below) reported in 2018 that human activities are estimated to have caused 1°C of global warming above pre-industrial levels already, and global warming is likely to reach 1.5°C between 2030 and 2052 if it continues at the current rate. 

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The global understanding is that a global temperature rise of 1.5°C  is the socially, economically, politically and scientifically safe limit to global warming by the end of this century, and to achieve this, the world needs to work to achieve 'net zero' emissions by 2050.

 

However, the world is currently way off course to meet this global target; emissions continue to increase and global temperatures continue to rise.

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IPCC SPECIAL REPORT ON THE IMPACT OF GLOBAL WARMING OF 1.5°C

 

The Intergovernmental Panel on Climate Change is the United Nations body for assessing the science related to climate change.

 

In 2013 the IPCC released its Fifth Assessment Report which concluded that climate change is real and human activities are the main cause. The report found alarming evidence that important tipping points - leading to irreversible changes to ecosystems and the climate system - may already have been passed. 

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In October 2018 the IPCC issued a special report on the impact of global warming of 1.5°C. Previous reports had focused on estimating the damage that would be caused if average temperatures were to rise by 2°C, however this report showed that many of the adverse impacts of climate change will come at the 1.5°C mark. (For example, coral reefs would decline by 70-90 percent with global warming of 1.5°C, whereas virtually all ( more than 99 percent) would be lost with a rise of 2ºC.). The report found that:- 

 

• limiting global warming to 1.5°C would require rapid, far-reaching and unprecedented changes in all aspects of society
   

• Global net human-caused emissions of carbon dioxide (CO₂) need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050. This means that any remaining emissions would need to be balanced by removing CO₂ from the air.

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(You can read the headline statements of the report here).

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NET ZERO EMISSIONS BY 2050

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The IPCC report is clear that global net emissions of greenhouse gases must be reduced to zero by 2050 in order to stabilise global temperatures.  Any scenario that does not involve a reduction to zero will not stop climate change.

 

'Net zero' means achieving an overall balance between emissions produced and emissions removed from the atmosphere through reduction measures (Carbon Dioxide Removal (CDR) . Net-zero emissions is a more realistic option than a gross-zero target (which would reduce emissions from all sources to zero) because it allows for some residual emissions from sectors where it would be too expensive, complex, or impossible to reduce emissions to zero

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CAUSES OF GLOBAL WARMING

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Human activities are the dominant factor in global warming since the mid 20th century;

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• the burning of fossil fuels (coal, oil and gas) is the biggest cause of global warming. Human activities have disturbed the world's natural carbon cycle by extracting long-buried fossil fuels and burning them for energy, releasing carbon dioxide (and other greenhouse gases) into the atmosphere.

 

As well as the burning of fossil fuels, other contributors to global warming include:-

 

• methane (which is released from landfills, natural gas, petroleum industries and agriculture (particularly from the digestive systems of grazing animals)
   

• nitrous oxide -  from fertilizers and other industrial processes
   

• deforestation - trees absorb huge amounts of carbon dioxide from the atmosphere, but are being destroyed on an industrial scale.  More than half of all deforestation is a result of farming, grazing of livestock, mining, and drilling (wildfires, forestry practices and urbanization account for the rest). Major culprits for the cutting down of forests include the production of palm oil (which is found in just about everything from food to household products and cosmetics), cattle ranching and soy plantations.

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IMPACT OF CLIMATE CHANGE

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We can already see the some of the impacts of climate change so far across the globe. How great the further impact of climate change will be depends on our success in reducing greenhouse gas emissions. Current and future impacts may include:-

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• extreme weather events - heat waves, droughts, flooding, wildfires

• changes in rainfall patterns affecting water supplies; increased risks of flooding, and drought conditions

• melting of mountain glaciers and the polar ice sheets causing rising sea levels

• higher sea levels, putting strain on coastal defences and putting coastal cities and settlements at risk from flooding

• ocean acidification and rising sea temperatures, threatening marine ecosystems around the world, particularly coral reefs

• negative effects on the production of major food crops such as wheat, rice, maize which may cause a growing gap between food demand and supply

• collapse of ecosystems and extinction of entire species, which will have an impact on food chains

• detrimental affects on human health including malnutrition; disease; heat exposure; health problems due to worsening air quality

• poverty in both developed and developing nations due to decreasing food production, extreme weather and health issues associated with climate change.

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Most climate change discussions look at what is most likely to happen, however, scientists have also identified the possibility that major elements of the earth's climate could be drastically altered if we pass 'tipping points', which may cause severe or abrupt changes (some of which may be irreversible). For example, the Arctic permafrost could thaw rapidly, releasing greenhouse gases that are currently ‘locked away’ and causing further rapid warming, and the great sheet of ice covering Greenland - which contains enough ice to cause up to 7 metres of sea level rise -  could melt almost entirely.  ​