Expert opinion on climate change

I regularly receive emails attacking basic Climate Science. Such attacks also appear frequently in some media publications.

It is possible to spend a great deal of time checking these claims, but this is not a viable option for most people.

A quicker method is to check the opinions of acknowledged experts, which would include our premier science organisations.

This post looks at the views of eight major science organisations and demonstrates that they all support the view that humans are warming the planet dangerously. It finishes with link to fifty more science organisations with similar views.

The UK MET Office

This post will reference many documents, which would require a great deal of time to fully read so I will start with a brief video from the UK MET Office:



The UK MET Office view is clear:

The current changes are very unusual and can not be explained simply as part of any natural cycle, such as El Nino and La Nina, which cause the warming and cooling of the tropical Pacific Ocean, which affects world temperature. Natural cycles can lead to periods with little or no warming and other periods with rapid warming. However, what is important is looking at the longer term trends in temperature,which are rising, and which scientists believe is almost certainly caused by human activity.

When studying climate change, scientists draw their evicence from many sources. Are humans contributing to the warming we are observing? Or could it be natural causes and changes to theclimate? Scientists, such as those at the Met Office Hadley Centre, are continuing to look at all the possible effects, both man-made and natural. However, it is widely understood that our emissions of greenhouse gases are causing changes to our climate.

At the MET Office FAQ site the following is given in answer to the question: "Can anything be done about Climate Change?"

On present evidence, global warming could be slowed if emissions of methane and carbon dioxide were reduced. The main artificial sources of these gases are (a) for methane - agriculture, emissions from landfill sites and natural gas and (b) for carbon dioxide - the burning of fossil fuels, cutting down and burning trees. This may seem to be something that only governments or large organisations can tackle, but the individual can also contribute significantly by, for example, not using a car unnecessarily and recycling.

For more information about the MET Office's view of Climate Change follow this link.

The Australian Academy of Science

The Australian academy of Science is Australia's foremost science organisation. In 2010 it released a report on climate science. The report can be found here.

The report begins with the following paragraph:

The Earth's climate has changed. The global average surface temperature has increased over the last century and many other associated changes have been observed. The available evidence implies that greenhouse gas emissions from human activities are the main cause. It is expected that if greenhouse gas emissions continue at business-as-usual rates, global temperatures will further increase significantly over the coming century and beyond.

The rest of the 24 page report provides the evidence to substantiate the claims in the first paragraph.

The CSIRO

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is Australia's premier science research organisation.

In 2011 CSIRO published a booklet called Climate Change: Science and Solutions for Australia. The document can be downloaded here.

The opening paragraph of the document states:

Climate change is one of the greatest ecological, economic, and social challenges facing us today.The scientific evidence that human activities are contributing to climate change is compelling, but society is increasingly seeking information about the nature of the evidence and what can be done in response to a changing climate. This book provides some of that much-needed information from some of Australia’s leading climate scientists.

Chapter 2 notes the following Key Messages

• Greenhouse gases (GHGs) influence the Earth’s climate because they interact with flows of heat energy in the atmosphere.

• The main GHGs influenced directly by human activities are carbon dioxide (CO2), methane, nitrous oxide,ozone, and synthetic gases. Water vapour, although an important GHG, is not influenced directly byhuman activities.

• The amount of warming produced by a given rise in GHG concentrations depends on ‘feedback’ processes in the climate system, which can either amplify or dampen a change. The net effect of all climate feedbacks is to amplify the warming caused by increasing CO2 and other GHGs of human origin.

• The atmospheric level of CO2 (the most important GHG influenced by human activities) rose from about280 ppm in 1800 to 386 ppm in 2009, and is currently increasing at nearly 2 ppm per year.

• CO2 levels are rising mainly because of the burning of fossil fuels and deforestation. Over half of thisCO2 input to the atmosphere is offset by natural CO2 ‘sinks’ in the land and oceans, which constitute a massive natural ecosystem service helping to mitigate humanity’s emissions.

• To have a 50:50 chance of keeping human-induced average global warming below 2ºC, it will be necessary to stop almost all CO2 emissions before cumulative emissions reach one trillion tonnes of carbon. The world has already emitted more than half of this quota since the industrial revolution, and (at current growth rates for CO2 emissions) the rest will be emitted by the middle of this century.

• Climate change is a risk management issue – the longer we take to act and the weaker our actions, the greater the risk of dangerous outcomes.

The Australian Bureau of Meteorology

The Australian Bureau of Meteorology has produced a document called State of the Climate 2010

The report can be found here.

The report concludes with the following observations:

Australia will be hotter in coming decades

Australian average temperatures are projected to rise by 0.6 to 1.5 ºC by 2030. If global greenhouse gas emissions continue to grow at rates consistent with past trends, warming is projected to be in the range of 2.2 to

5.0 ºC by 2070. Warming is projected to be lower near the coast and in Tasmania and higher in central and north-western Australia. These changes will be felt through an increase in the number of hot days.

Much of Australia will be drier in coming decades

In Australia compared to the period 1981-2000, decreases in rainfall are likely in the decades to come in southern areas of Australia during winter, in southern and eastern areas during spring, and in south-west Western Australia during autumn. An increase in the number of dry days is expected across the country, but it is likely that there will be an increase in intense rainfall events in many areas.

It is very likely that human activities have caused most of the global warming observed since 1950

There is greater than 90% certainty that increases in greenhouse gas emissions have caused most of the global warming since the mid-20th century. International research shows that it is extremely unlikely that the observed warming could be explained by natural causes alone. Evidence of human influence has been detected in ocean warming, sea-level rise, continental-average temperatures, temperature extremes and wind patterns. CSIRO research has shown that higher greenhouse gas levels are likely to have caused about half of the winter rainfall reduction in south-west Western Australia.

Climate change is real

Our observations clearly demonstrate that climate change is real. CSIRO and the Bureau of Meteorology will continue to provide observations and research so that Australia’s responses are underpinned by science of the highest quality.

UPDATE: The 2012 State of the Climate Report has been released and can be found at this link.


US Academy of Science

The US Academy of Science (the peak Science body of the US) has also produced a report on climate science which can be accessed here.

The first conclusion of the report (found on page 3) is:

Climate change is occurring, is caused largely by human activities, and poses significant risks for—and in many cases is already affecting—a broad range of human and natural systems

That conclusion is supported by the following dot points:

• Earth is warming. Detailed observations of surface temperature assembled
  and analyzed by several different research groups show that the planet’s average surface temperature was 1.4ºF (0.8ºC) warmer during the first decade of the 21st century than during the first decade of the 20th century, with the most pronounced warming over the past three decades. These data are corroborated by a variety of independent observations that indicate warming in other parts of the Earth system, including the cryosphere (snow- and ice covered regions), the lower atmosphere, and the oceans.

• Most of the warming over the last several decades can be attributed to human activities that release carbon dioxide (CO2) and other heat-trapping greenhouse gases (GHGs) into the atmosphere. The burning of fossil fuels—coal, oil, and natural gas—for energy is the single largest human driver of climate change, but agriculture, forest clearing, and certain industrial activities also make significant contributions.

• Natural climate variability leads to year-to-year and decade-to-decade fluctuations in temperature and other climate variables, as well as substantial regional differences, but cannot explain or offset the long-term warming trend.

• Global warming is closely associated with a broad spectrum of other changes, such as increases in the frequency of intense rainfall, decreases in Northern Hemisphere snow cover and Arctic sea ice, warmer and more frequent hot days and nights, rising sea levels, and widespread ocean acidification.

Joint Academies Statement

Thirteen Academies of Science have regularly made a statement on climate change. The academies are those of: the US, UK. France, Germany, Japan, Canada, Italy, China, India, Brazil, Mexico, Russia and South Africa, the G8 plus 5 group.

In their most recent statement (found here) they give the following recommendations:

Recognizing the vital role that low carbon energy systems must play in facilitating a sustainable global economy, the G8+5 nations need to seize all
opportunities to coordinate our simultaneous work on the climate and economic agendas, and to build global collaboration.

We call on all governments to:

• agree at the UNFCCC negotiations in Copenhagen to adopt a long-term global goal and near-term emission reduction targets that will deliver an approximately 50% reduction in global emissions from 1990 levels by 2050;

• significantly increase fundamental international research on the earth’s climate, on low carbon and climate resilient technologies, and on ways to protect and enhance the resilience of natural systems to climate change;

• identify the common strategic priorities for developing and implementing environmentally sustainable technologies for adaptation and mitigation;

• collaborate in the implementation of low carbon and climate-resilient infrastructure and technologies, and in the implementation of innovative incentives,
  through the use of economic and regulatory instruments, to accelerate adoption of clean “green” technologies;

• support and enable developing countries’ access to and use of the technologies needed to deliver a sustainable low carbon energy future;

• pursue the development, demonstration and deployment of economically efficient and technologically safe CCS, and explore the establishment of standards for CCS;

• pursue international cooperation on safe and secure nuclear power capacity, the safe disposal of nuclear waste, and the reduction of the risk of proliferation;

• substantially increase investment into the development and deployment of technologies for adaptation, and increase funding specifically for the most vulnerable countries.

Education and public awareness programmes will be essential as we pursue this agenda. We must build on the current enthusiasm and engagement of a younger generation.

The US National Oceanic and Atmospheric Administration (NOAA)

NOAA is one of the major oceanic and atmospheric research and reporting organisations. Each year NOAA produces a document called State of the Climate. The full report for 2010 can be downloaded here and the summary here.

Page 6 of the summary:

The World Continues to Warm

• Multiple indicators, same bottom line conclusion

Consistent and unmistakable signal from the top of the atmosphere to the bottom of the oceans

The conclusion makes the following points:

• 2010 global average surface temperature among the two warmest on record

• 2010 report tracks 41 climate indicators. Long-term trends continue to show the world is warming

The Royal Society

The Royal Society is the most prestigious science organisation in the world. It is Britain's National Academy of Science.

The Royal Society produced a document on Climate Science in 2010, which can be downloaded here.

The report begins as follows:

Changes in climate have significant implications for present lives, for future generations and for ecosystems on which humanity depends. Consequently, climate change has been and continues to be the subject of intensive scientific research and public debate.

There is strong evidence that the warming of the Earth over the last half-century has

been caused largely by human activity, such as the burning of fossil fuels and changes in land use, including agriculture and deforestation. The size of future temperature increases and other aspects of climate change, especially at the regional scale, are still subject to uncertainty. Nevertheless, the risks associated with some of these changes are substantial. It is important that decision makers have access to climate science of the highest quality, and can take account of its findings in formulating appropriate responses.

I could keep discussing the views of more science organisations, but this post is already quite long.

UPDATE

The World Bank

In November 2012 the World Bank released a report titled: "Turn Down the Heat:     Why a 4⁰ Warmer World Must Be Avoided. Here is a link to the document.

The first paragraph of the Executive Summary sets the tone of the whole document.

Without further commitments and action to reduce greenhouse gas emissions, the world is likely to warm by more than 3°C above the preindustrial climate. Even with the current mitigation commitments and pledges fully implemented, there is roughly a 20 percent likelihood of exceeding 4°C by 2100. If they are not met, a warming of 4°C could occur as early as the 2060s. Such a warming level and associated sea-level rise of 0.5 to 1 meter, or more, by 2100 would not be the end point: a further warming to levels over 6°C, with several meters of sea-level rise, would likely occur over the following centuries.


PricewaterhouseCoopers

PricewaterhouseCoopers trades as PwC. In November 2012 it released a report called: "Too late for two degrees? Low carbon economy index 2012". The report can be downloaded from this link. Discussion of this report can be found in this page of the PwC website.

The video below is from the PwC website linked to above. It makes a number of important points: 1. The longer we wait to get serious about emissions reduction the harder the task will become, 2. To refuse to reduce emissions is extremely dangerous, and, 3. Countries that develop the new technologies to meet the challenge will have an important new source of wealth.



To quote from page 2 the report:

The PwC Low Carbon Economy Index evaluates the rate of decarbonisation of the global economy that is needed to limit warming to 2°C. This is based on a carbon budget that would stabilise atmospheric carbon dioxide concentrations at 450 ppm and give a 50% probability of limiting warming to 2°C.

This report shows that global carbon intensity decreased between 2000 and 2011 by around 0.8% a year. In 2011, carbon intensity decreased by just 0.7%. The global economy now needs to cut carbon intensity by 5.1% every year from now to 2050 to achieve this carbon budget. This required rate of decarbonisation has not been seen even in a single year since the mid-20th century when these records began. Keeping to the 2°C carbon budget will require unprecedented and sustained reductions over four decades.

Governments’ ambitions to limit warming to 2°

For information on another fifty science organisations that support the climate consensus position follow this link.