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Published: 8 September 2014

99.999 per cent certainty humans are driving global warming: new study

Philip Kokic, Mark Howden and Steven Crimp

There is less than 1 chance in 100,000 that global average temperature over the past 60 years would have been as high without human-caused greenhouse gas emissions, our new research shows.

We already know there is overwhelming scientific consensus among almost all actively publishing climate scientists, who agree that humans are causing global warming. The reason for this consensus of scientists is the consensus of evidence – strengthened even further by these new findings.
We already know there is overwhelming scientific consensus among almost all actively publishing climate scientists, who agree that humans are causing global warming. The reason for this consensus of scientists is the consensus of evidence – strengthened even further by these new findings.

Published in the journal Climate Risk Management last week, our research is the first to quantify the probability of historical changes in global temperatures and examine the links to greenhouse gas emissions using rigorous statistical techniques.

Our new CSIRO work provides an objective assessment linking global temperature increases to human activity, which points to a close to certain probability exceeding 99.999 per cent.

Our work extends existing approaches undertaken internationally to detect climate change and attribute it to human or natural causes. The 2013 Intergovernmental Panel on Climate Change Fifth Assessment Report provided an expert consensus that:

    It is extremely likely [defined as 95-100 per cent certainty] that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic [human-caused] increase in greenhouse gas concentrations and other anthropogenic forcings together.

Decades of extraordinary temperatures

July 2014 was the 353rd consecutive month in which global land and ocean average surface temperature exceeded the 20th-century monthly average. The last time the global average surface temperature fell below that 20th-century monthly average was in February 1985, as reported by the US-based National Climate Data Center.

This means that anyone born after February 1985 has not lived a single month where the global temperature was below the long-term average for that month.

We developed a statistical model that related global temperature to various well-known drivers of temperature variation, including El Niño, solar radiation, volcanic aerosols and greenhouse gas concentrations. We tested it to make sure it worked on the historical record and then re-ran it with and without the human influence of greenhouse gas emissions.

Our analysis showed that the probability of getting the same run of warmer-than-average months without the human influence was less than 1 chance in 100,000.

We do not use physical models of Earth’s climate, but observational data and rigorous statistical analysis, which has the advantage that it provides independent validation of the results.

Detecting and measuring human influence

Our research team also explored the chance of relatively short periods of declining global temperature. We found that rather than being an indicator that global warming is not occurring, the observed number of cooling periods in the past 60 years strongly reinforces the case for human influence.

We identified periods of declining temperature by using a moving 10-year window (1950 to 1959, 1951 to 1960, 1952 to 1961, etc.) through the entire 60-year record. We identified 11 such short time periods where global temperatures declined.

Our analysis showed that in the absence of human-caused greenhouse gas emissions, there would have been more than twice as many periods of short-term cooling than are found in the observed data.

There was less than 1 chance in 100,000 of observing 11 or fewer such events without the effects of human greenhouse gas emissions.

CSIRO scientists Dr Steve Rintoul, Dr John Church and Dr Pep Canadell explain how and why the Earth’s climate is warming.

Credit: CSIRO

The problem and the solution

Why is this research important? For a start, it might help put to rest some common misunderstandings about there being no link between human activity and the observed, long-term trend of increasing global temperatures.

Our analysis – as well as the work of many others – shows beyond reasonable doubt that humans are contributing to significant changes in our climate.

Good risk management is all about identifying the most likely causes of a problem, and then acting to reduce those risks. Some of the projected impacts of climate change can be avoided, reduced or delayed by effective reduction in global net greenhouse gas emissions and by effective adaptation to the changing climate.

Ignoring the problem is no longer an option. If we are thinking about action to respond to climate change or doing nothing, with a probability exceeding 99.999 per cent that the warming we are seeing is human-induced, we certainly shouldn’t be taking the chance of doing nothing.

Dr Philip Kokic is a CSIRO statistician with 25 years’ experience in analysis of survey data, climate risk modelling and econometric analysis. Dr Mark Howden leads CSIRO research on the impacts of climate variability and change on agricultural and urban systems. Mr Steven Crimp leads a CSIRO research team investigating the resilience of Australian cropping systems under climate change. This article was originally published on The Conversation.







Published: 4 July 2011

Assured sustainability reporting – navigating obligations

Nick Fleming

As the way in which organisations address environmental, social and governance (ESG) issues comes under increasing scrutiny, sustainability reporting is gathering importance and momentum. Yet reporting must be seen as a product of sustainable business practices, not the focus of it.

Emphasis on more robust sustainability reporting is helping to drive the wider assessment and reform of companies’ associated supply chains and logistics infrastructure.
Emphasis on more robust sustainability reporting is helping to drive the wider assessment and reform of companies’ associated supply chains and logistics infrastructure.
Credit: iStockphoto

While sustainability reporting is new territory for some organisations, many leading businesses have been engaged in reporting for over a decade. Indeed, sustainability reporting is typically one of the first vehicles for engagement with the topic and issues of sustainability, often at the encouragement of a few passionate staff.

However, the call for greater organisational accountability and transparency is growing. An increasing number of shareholder resolutions are placing pressure on company boards to ensure they are effectively identifying, disclosing and addressing ESG risks. Institutional investors are already using ESG data to differentiate firms and guide investment decisions.1

Powerful customers are also forcing their suppliers to become more transparent. The classic example is Walmart, which launched a supplier sustainability initiative in July 2009. Locally, Woolworths recently announced its own Sustainable Fish Sourcing Strategy.2

There is also an expectation for assurance. This reflects a stakeholder desire for reports to be relevant, reliable and free from bias, while the reporting organisation wishes to build a case for lower costs for finance and insurance. This all takes time and money; reporting can be a costly exercise and carries risks.

The banking sector provides an insight to the challenges posed by sustainability reporting. In Australia, banks have typically lead sustainability reporting and have performed well against international benchmarks such as the Dow Jones Sustainability Index. Yet this year, the big four banks have been publically criticised over their involvement with coal-fired power stations.3 People ask how an organisation that receives sustainability accolades can also finance environmental pollution. This questions the connectivity between sustainability reporting and governance.

Scrutiny is also being applied by the regulators. The Australian Competition and Consumer Commission has prosecuted cases against companies such as GM Holden and Prime Carbon for overstating their ‘green’ credentials. It’s clear that inaccurate communication on ESG matters presents serious risks to an organisation’s reputation – and that of the rating or assurance agency.

These issues have been behind recent reviews of reporting guidelines and benchmarking methods.4,5 The reviews found that ratings and reporting tend to be backward-looking measures of compliance with ‘good practice’, failing to enable a meaningful assessment of an organisation’s ability to create and sustain value, in the short and longer term.

What’s lacking is adequate interrogation and reporting of the strategic capabilities and the core competencies required to underpin business continuity and delivery of sustainable outcomes; that is, a truly sustainable enterprise.

However, the push for integrated financial and non-financial (sustainability) reporting may offer a silver lining – the trigger to focus conversations among executives and boards about the things that will drive genuine business continuity, profitability and sustainability. Without these conversations, there will neither be the understanding, focus nor commitment to cultivate truly sustainable enterprises.

The adage ‘What gets measured gets managed’ remains true; as does ‘It’s what you do, not what you say, that counts’. Reporting without subsequent actions to manage risks and create value is meaningless, and arguably harmful.

While there are growing market and stakeholder pressures for integrated reporting of financial and ESG matters, reporting should only be entered into with an eye on:

  1. material business risks

  2. core competencies for organisational continuity

  3. a core set of meaningful performance measures that offer real insight

  4. integrating reporting into governance

  5. commitment to real action in response to identified risks and opportunities.

Organisations that assume this approach take sustainability reporting beyond a ‘nice?to?have’ PR exercise to a ‘must?have’ business improvement tool. It’s a factor in the superior financial performance demonstrated by ethical and sustainable organisations. Getting it right is good for business – and good for communities.

Dr Nick Fleming is Chief Sustainability Officer Sinclair Knight Merz, leading the application of sustainability thinking in business operations and client services. Through his Sustainable Enterprise column, Nick provides insight to how businesses and organisations are effectively putting sustainability theory into practice.


1 Ernst & Young (2011). Shareholders press boards on social and environmental risks. tinyurl.com/social-environmental-risks
2 tinyurl.com/sustainable-fish
3 Greenpeace (2011). Pillars of pollution. www.greenpeace.org.au/climate/GI-profundo.php
4 Eccles RG, Cheng B, Saltzman D (Eds) (2010). The landscape of integrated reporting: reflections and next steps. Harvard Business School. tinyurl.com/integrated-reporting
5 SustainAbility (2011). Rate the raters: uncovering best practices. www.sustainability.com/library/rate-the-raters-phase-one




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