Climate Change Basics

You can find basic information about climate change, what's happening and what we need to do at these reputable Climate Change education web sites:  (video) (NASA) (facts) (interactive) (FAQs) (New Scientist Magazine) (beginner's facts) (US National Centre for Atmospheric Research) (Australian government's Dept. Climate Change & Energy Efficiency) (FAQ facts) (Encyclopedia of Earth) (animation) (Oxford University)  (FAQs) (UK Met Office)  (The Global Warming Debate - a layman's guide).
  (Peter Sinclair's "What We Know about Climate Change" video) (Scott Mandia's FAQ site) (climate science from climate scientists) (debunking the myths of climate change) (Researching and reporting the science and impacts of climate change

You can also download a comprehensive Climatology Timeline (PDF document) from the bottom of this page

How can we be sure that there really is a problem that needs addressing, and who should be believed on climate change?

Aside from the work of the UN's Intergovernmental Panel on Climate Change, strong statements affirming the reality of human contribution to climate change have been released by the National Academies of Science of many countries, including: Australia, Belgium, Brazil, Canada, the Caribbean, China, France, Germany, India, Indonesia, Ireland, Italy, Japan, Malaysia, Mexico, New Zealand, Russia, South Africa, Sweden, the US and UK.

Reviews have also been undertaken of the scientific literature and again and again the finding is that the vast majority of qualified scientists with expertise in the relevant areas support the view that humans are influencing the climate.

A large number of professional scientific bodies and associations have also affirmed the reality of human influence on the climate, including, in the United States, the National Oceanic and Atmospheric Administration, the Environmental Protection Agency, NASA's Goddard Institute of Space Studies, the American Geophysical Union, the American Institute of Physics, the National Center for Atmospheric Research, the American Meteorological Society, the American Association for the Advancement of Science, as well as the Royal Society of the UK, the Canadian Meteorological and Oceanographic Society, and Australia’s CSIRO.

The main reason these scientists are so concerned is because they cannot explain the observed changes over the past century without taking into account rising greenhouse gas levels. Other factors such as sun spots, volcanic activity, changes to the Earth's orbit and cosmic rays have all been considered, but none of these have shown any significant changes that would explain the planet's recent warming, in fact their levels of activity (& therefore influence) have either not changed at all, or should be tending to slightly cool the planet.  In other words, they just aren't having a significant impact.

Climate science has been studied for almost two hundred years now*.  In that time the basic physics and chemistry of the planetary greenhouse effect has become widely accepted and well understood, and the climatic changes now being observed fit well with the predictions, over the last seventy years, that were made about the effect of human induced carbon pollution on the earth's atmosphere, as scientists have become ever more certain as to what's happening, and why, and what effect on the climate we can expect in future.

There is rarely total unanimity on anything as complex in the Earth sciences, so by any measure, the agreement of more than 96% of scientists with demonstrated expertise in the field, plus the backing of all of the world’s major national academies of science and major professional scientific associations represents an extremely strong professional consensus on the core issue that the climate is warming and that humans are contributing to the problem through excessive greenhouse gas emissions.

Of those handful of respected and relevant scientists who don't fully agree with the majority view, they generally accept the general thrust that the globe is indeed warming to some degree due to human caused atmospheric pollution, but they tend to differ on some of the finer points, such as the relative importance of the other factors, the amount of warming expected or the amount of climate sensitivity caused by greenhouse gas emissions.

And yet there appears to be a raging "debate" on the web and in the popular press.  How can this be? Much misinformation is being fed to the media by a well oiled denialist machine which is loudly supported by the "paid liars & fraudsters" of the fossil fuel industry**; "World Government" conspiracy theorists; opportunistic and ideologically driven politicians; scared, non-scientific amateurs; self-important opinion writers and "grumpy old academics" (often geologists, meteorologists & economists) who perhaps feel that, with their status and the relevance of their work diminished, and their careers on the wane, they can only get attention by expousing contrarian views to the media. These writers tend to place themselves above collected scientific wisdom using simplistic, unsubstantiated popular chants.  Hence isolated typographical errors, "smoke & mirror" statistics on web sites showing dropping temperature charts, or the significance of some poorly placed & maintained weather stations become more "real" than the heat waves or advancing changes of seasons do outside their own front door.  The animals and plants of this Earth "know" that the planet is warming, and at an unprecedented rate. It's been estimated that 88% of changes observed over the past two decades in species distributions, morphological characteristics, phenologies (life cycle timing), and even genes that control heat tolerance, are in the direction of warming.

Do the so called "sceptics" who question the science of climate change do so in other areas of their lives? Do they refuse a doctor's advice when seriously ill, naively believing anything they find on the internet instead?  Do they quibble with aviation engineers before they board a plane? Or do they distrust science only when it suits them and their beliefs?

This is not to denigate true science skeptics, who would rationally research and evaluate available evidence from all sides of an argument equally & without prejudice, in order to reach an informed position.  Such methodical & reasoned enquiries are a core element of the scientific method, alongside the testing of hypotheses against the criteria of predictability & repeatability. Relying on personal beliefs and convenient myths and factoids is not.

The harsh reality of climate change is very frightening, no doubt, and just about everyone would want to be able to wish it away, but when weighing the risk of doing nothing compared to that of taking action, each of us needs to face up to and act on the dangers of climate change, for the common good of future generations, and simply because it's the right thing to do.

* for more on the fascinating history of climate science and politics, see Climatology Timeline (Adobe PDF document) at the bottom of this page.

** for a thorough expose of who's actually behind the professional denialist industry, see:

What about the climate models, aren't they flawed?

No-one claims that climate models are perfect, essentially because they are attempting to replicate an enormously complex and sometimes chaotic global system, but climate models are based on fundamental physics and chemistry and have been able to replicate past observations to a good degree of accuracy.  They have also anticipated effects such as the global cooling effects resulting from major volcanic eruptions such as Mt Agung in Bali in 1963 and Mt Pinatubo in the Philippines in 1991, as well as the more recent natural internal variability.

But even if climate models and their predictions are completely ignored, recent summaries published by the International Alliance of Research Universities [Synthesis Report from Climate Change 2009] and the Pew Center on Global Climate Change show that the majority of the new scientific insights are based entirely or partially on direct observations of climate change (as opposed to forecasts or estimates based on models).

The most important findings are:

- The link between fossil fuel emissions and climate change became clearer and stronger.

- Changing precipitation trends are larger than hitherto predicted and are already impacting crops, ecosystems and human health.

- Ocean acidification severely threatens coral reefs, shellfish and fisheries. Coral reefs may altogether stop growing by 2050, and eventually become extinct.

- New estimates of average global sea level rise for this century set the upper end to 2m instead of 0.6 m. (This is without counting the effect of abrupt events causing sea rise, the chances of which actually be seem to be greater than previously understood.) Both the Greenland land ice and the Antarctic land ice and ice shelves are thinning and collapsing faster than previously understood.

- Arctic sea ice is also melting faster than projected. This causes the Arctic region to warm up more, and the permafrost to release methane faster than previously thought.

- Since 2000, the growth rate of actual CO2 emissions has tracked – and in fact exceeded - the most pessimistic (i.e., the fastest growth rate for CO2 emissions) of the IPCC scenarios.  As a result, atmospheric CO2 concentration increased 33 percent faster between 2000 – 2007 than in the 1990s.

Furthermore, in March 2010 (and again in 2012) the CSIRO and the Australian Bureau of Meteorology together produced a snapshot summary of Australia’s changing climate, called "State of the Climate". It is sourced from peer reviewed data on temperature, rainfall, sea level, ocean acidification, and carbon dioxide and methane levels in the atmosphere and it shows the actual state of climate change across the country.  The Bureau of Meteorology has been observing and reporting on weather in Australia for over 100 years, and CSIRO has been conducting atmospheric and marine research for over 60 years.

You can download their 
bi-annual reports at

Similarly, in August 2010 the Australian Academy of Science published their “The Science of Climate Change: Questions and Answers”, aimed at addressing the confusion created by contradictory information in the public domain. 

You can download their report at

In general, all this observed climate change is proceeding at a more rapid pace than ever anticipated by previous estimates or model projections. Sea level is rising, global ice cover is diminishing, and biological systems are disturbed. Recent revisions of projected changes are higher than earlier estimates; the IPCC projections published in 2007 now appear rather conservative in light of more recent observations and improved modeling techniques. With unabated emissions, many trends in climate will likely accelerate, leading to an increasing risk of abrupt or irreversible climatic shifts.

Rapid, sustained and effective mitigation is required more than ever before. Setting and reaching strong targets for 2020 this year would lower the risk of crossing tipping points, and would make meeting the targets for 2050 cheaper and safer. Adoption and implementation of policies that promote energy efficiency, low-carbon technologies and the reduction of waste is the key to effective mitigation.

Without mitigation, the disruption of ecosystems spills over into social problems. Societies are highly vulnerable to even modest levels of climate change.  Poor communities are particularly at risk. Temperature rises above 2°C are likely to cause major societal disruptions through the rest of the century. Climate change will also have strongly differential effects on present and future generations. Tackling climate change is therefore integral to enhancing social development and equity throughout the world. Linking climate change with human rights issues and democratic values is crucial for moving societies towards resilience and more sustainable development.

Note: text quoted above on the most important findings of the IARU's Synthesis Report and the Pew Center is courtesy of H.E. Laszlo Solyom, President of the Republic of Hungary, 2009.

Climate Action Hobart,
Jul 15, 2018, 8:32 PM