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Critical Issues: Climate Change

Climate Change is happening and human activities are certainly the cause.

There is overwhelming evidence that Global Warming and associated Climate Changes are happening. The impacts of future climate change will be dramatic without a significant and permanent reduction in greenhouse gas emissions. Rising global temperatures will bring changes in weather patterns, rising sea levels and increased frequency and intensity of extreme weather.

Climate scientists agree - Global Warming is a fact, we are experiencing it now. The ten warmest years on record have all occurred since 1991. The increasing incidence of heat waves, storms, floods and forest fires, along with rapidly melting glaciers and ice-sheets are all indicators of the direction of change.

We need to avoid making the problem worse, so cutting carbon emissions is a priority. But all of us - individuals, businesses, Government and public authorities, in all countries - must also adapt our behaviour to respond to the challenges of climate change.


Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.
(IPCC, September 2013, Twelfth Session of Working Group I Approved Summary for Policymakers )

What is Climate Change?
The Greenhouse Effect
 

The release of Greenhouse Gases from the burning of fossil fuels and widespread changes in land use are responsible for the observed world-wide temperature increase. The dominant Greenhouse Gas is Carbon Dioxide (CO2).

Failure to properly address climate changes will force our hand. National, regional & global responses to Global Warming tend to underestimate both the magnitude of the problem, as well as the timeframe in which dramatic changes are likely to occur.

This gap between scientists and decision makers is the most worrying aspect. Furthermore, bad as it is for the developed world, it is of most immediate concern to people living in developing countries: where lives and livelihoods are likely to be threatened earlier and more radically.



Total Carbon emissions from fossil-fuels
(million metric tons of Carbon)
Boden, T.A., G. Marland, and R.J. Andres. 2016. Global, Regional, and National Fossil-Fuel CO2 Emissions. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A. doi 10.3334/CDIAC/00001_V2016. http://cdiac.ornl.gov/trends/emis/glo_2013.html

 

Surface Temperature

Land-ocean temperature index, 1880 to present, with base period 1951-1980. The solid black line is the global annual mean and the solid red line is the five-year lowess smooth. The blue uncertainty bars (95% confidence limit) account only for incomplete spatial sampling. https://data.giss.nasa.gov/gistemp/graphs/


The U.S. Energy Information Administration (EIA)
projects 48% increase in world energy consumption by 2040. http://www.eia.gov/todayinenergy/detail.php?id=26212


The global warming observed over the past 50 years is due primarily to human-induced emissions of heat-trapping gases. These emissions come mainly from the burning of fossil fuels (coal, oil, and gas), with additional contributions resulting from the forest clearance, modern agricultural practices, and other activities.

Since 1751 approximately 329 billion tons of carbon have been released to the atmosphere from the consumption of fossil fuels and cement production. Half of these emissions have occurred since the mid 1970s. The 2006 global fossil-fuel carbon emission estimate, 8230 million metric tons of carbon, represents an all-time high and a 3.2% increase from 2005.

Globally, liquid and solid fuels accounted for 76.6% of the emissions from fossil-fuel burning and cement production in 2006. Combustion of gas fuels (e.g., natural gas) accounted for 18.5% (1521 million metric tons of carbon) of the total emissions from fossil fuels in 2006 and reflects a gradually increasing global utilization of natural gas. Emissions from cement production (348 million metric tons of carbon in 2006) have more than doubled since the mid 1970s and now represent 4.2% of global CO2 releases from fossil-fuel burning and cement production. Gas flaring, which accounted for roughly 2% of global emissions during the 1970s, now accounts for less than 1% of global fossil-fuel releases.

 
Anthropogenic Carbon Release Rate Unprecedented During the Past 66 Million Years.
We are now putting carbon into the atmosphere at a rate unprecedented since at least the age of the dinosaurs. Researchers have examined ocean sediments laid down during the Palaeocene-Eocene Thermal Maximum -(PETM) a dramatic warming event some 56 million years ago. They find the amount of CO2 going into the air at the onset of the PETM was four billion tonnes a year at most. Today's figure is 10 times as big.
Zeebe, R. E., A. Ridgwell, and J. C. Zachos. (2016). Anthropogenic carbon release rate unprecedented during the past 66 million years. Nature Geoscience, doi:10.1038/NGEO2681.
  http://www.soest.hawaii.edu/oceanography/faculty/zeebe_files/Publications.html
http://www.bbc.co.uk/news/science-environment-35867438
http://www.nature.com/ngeo/journal/v9/n4/full/ngeo2681.html


2016:
NOAA data shows that CO2 levels make largest recorded annual leap. Atmospheric concentrations of carbon dioxide last year rose by the biggest margin since records began. CO2 levels in the air have increased over 40% since 1880, as industry increased emissions. 2015 was the hottest year on record, according to multiple weather agencies. The last time the Earth experienced such a sustained CO2 rise was between 11,000 and 17,000 years ago, in which period CO2 jumped by 80ppm. Today's rate is 200 times faster.
  http://www.theguardian.com/environment/2016/mar/10/co2-levels-make-largest-recorded-annual-leap-noaa-data-shows

https://www.esrl.noaa.gov/gmd/ccgg/trends/full.html

The carbon dioxide data on Mauna Loa constitute the longest record of direct measurements of CO2 in the atmosphere.


Global Warming or Climate Change? What’s the difference?

The terms Global Warming & Climate Change, or more correctly Anthropogenic Climate Change, seem in current practice to be interchangeable. The records sow that the plannet is heating up. The consensus amongst the scientific community is that this warming is the result of human activity and largely due to pollution by greenhouse gases released to the atmosphere. This rise in global mean temperature is termed Global Warming. The primary consequences of global warming are a series of local climate changes, and these are having an increasing impact on man's activities, and the environment as a whole - thus the generic expression Climate Change.

Global Warming is the problem. Climate Change is the challenge. Development that is truely sustainable is the medium to longer term solution. In the immediate time frame we must both mitigate global warming to stop it getting worse, and ALSO adapt to the local climate changes that are already with us, and deal with the impacts of these changes.


What is Climate Change?

Climate is the description of an average set of weather conditions over a period of time. Climate Change is therefore an indication of how these conditions are changing over time.

Hstorical observations and ongoing data collection provides evidence that climate change has been happening in recent decades. Some of that evidence obviously comes from temperature records. Recoreds of sea level rise indicate that sea level rise has been increasing, and this is consistent with global warming. Probably the most compelling evidence comes from the retreat of glaciers and sea ice, in for example the northern Arctic. This is very clear evidence which is linked to global warming that warming is having an impact on the whole globe.

Global warming / Climate Change is probably the most important issue to face our generation, and quite possibly any generation in history. The worldwide scientific community is virtually unanimous in its agreement that global warming is happening, that that it's our fault. If we let it get out of our control, the consequences - which will already begin occurring in most of our lifetimes - will be catastrophic. Just some of the consequences that can be reasonably expected are rising sea levels, more frequent and more severe natural disasters, large-scale food shortages, plagues, massive species extinctions, unprecedented numbers of refugees, intensified ethnic and political tensions, and a global economic depression the likes of which no one has ever seen.


The Greenhouse Effect

The greenhouse effect is a process by which radiative energy leaving the planetary surface is absorbed by a range of atmospheric gases, called greenhouse gases. This energy is then transferred to other components of the atmosphere, and is re-radiated in all directions, including back down towards the surface of the plannet.

An increase in the quantity of greenhouse gasses with therefore increase this greenhouse effect and will ultimately result in increased temperatures on the surface of the plannet.

 

 

 

 

Page last updated February 4, 2017