The conclusions will be published into a full synthesis report June 2009.

The six preliminary key messages are:

Key Message 1: Climatic Trends

Recent observations confirm that, given high rates of observed emissions, the worst-case IPCC scenario trajectories (or even worse) are being realised. For many key parameters, the climate system is already moving beyond the patterns of natural variability within which our society and economy have developed and thrived. These parameters include global mean surface temperature, sea-level rise, ocean and ice sheet dynamics, ocean acidification, and extreme climatic events. There is a significant risk that many of the trends will accelerate, leading to an increasing risk of abrupt or irreversible climatic shifts.

Key Message 2: Social disruption

The research community is providing much more information to support discussions on "dangerous climate change." Recent observations show that societies are highly vulnerable to even modest levels of climate change, with poor nations and communities particularly at risk. Temperature rises above 2 degrees Celsius will be very difficult for contemporary societies to cope with, and will increase the level of climate disruption through the rest of the century.

Key Message 3: Long-Term Strategy

Rapid, sustained, and effective mitigation based on coordinated global and regional action is required to avoid "dangerous climate change" regardless of how it is defined. Weaker targets for 2020 increase the risk of crossing tipping points and make the task of meeting 2050 targets more difficult. Delay in initiating effective mitigation actions increases significantly the long-term social and economic costs of both adaptation and mitigation.

Key Message 4 - Equity Dimensions

Climate change is having, and will have, strongly differential effects on people within and between countries and regions, on this generation and future generations, and on human societies and the natural world. An effective, well-funded adaptation safety net is required for those people least capable of coping with climate change impacts, and a common but differentiated mitigation strategy is needed to protect the poor and most vulnerable.

Key Message 5: Inaction is Inexcusable

There is no excuse for inaction. We already have many tools and approaches -- economic, technological, behavioural, management -- to deal effectively with the climate change challenge. But they must be vigorously and widely implemented to achieve the societal transformation required to decarbonise economies. A wide range of benefits will flow from a concerted effort to alter our energy economy now, including sustainable energy job growth, reductions in the health and economic costs of climate change, and the restoration of ecosystems and revitalisation of ecosystem services.

Key Message 6: Meeting the Challenge

To achieve the societal transformation required to meet the climate change challenge, we must overcome a number of significant constraints and seize critical opportunities. These include reducing inertia in social and economic systems; building on a growing public desire for governments to act on climate change; removing implicit and explicit subsidies; reducing the influence of vested interests that increase emissions and reduce resilience; enabling the shifts from ineffective governance and weak institutions to innovative leadership in government, the private sector and civil society; and engaging society in the transition to norms and practices that foster sustainability.

Note: If no author is given, the source is cited instead.

• Climate
• Global Warming
• Environmental Policy

• Environmental Policies
• Resource Shortage
• World Development

• Consensus of scientists regarding global warming
• Instrumental temperature record
• Temperature record
• Scientific opinion on climate change
• Climate model
• Greenland ice sheet