This guide sets out the main facts and uncertainties regarding climate change, and helps provide Australians with policy-relevant, but not policy-prescriptive, advice and source material It is largely based on, and consistent with, the Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC TAR) published in 2001 However, this guide has been substantially updated with relevant summaries of the latest international and Australian observations, scientific developments, and studies regarding the impacts of, and adaptation to climate change in Australia

While much progress in understanding the climate change issue has been made, uncertainties continue to exist about aspects of the climate change science, and regarding societal developments that will affect the extent of future climate change and societal vulnerability Some impacts of climate change are now inevitable However, more certainty and understanding is needed to guide decision-makers towards the most effective and cost-efficient means to adapt to climate changes in the near-term (next decade), and to avoid unacceptably large climate changes in the longer term (multi-decades to centuries) through emissions reductions measures

The high probability of at least some global warming, given the inertia in the climate and socioeconomic systems, means that some adaptation will be necessary This will be most efficient if the location- and activity-specific nature of the likely impacts is taken into account Considerable uncertainties about location-specific impacts can be further reduced by targeted research, while caseby- case assessments of adaptation strategies will be needed for many particular sectors and locations

Any emission reductions will progressively reduce the likelihood of impacts at the high end of the existing large range of emissions scenarios, and thus help to avoid the potentially most damaging climate change possibilities Thus, in order to establish minimum objectives for emissions reductions, attention needs to be given to the more extreme possibilities to which adaptation may not be possible These will determine critical greenhouse gas concentration thresholds that must be avoided if the objective of the United Nations Framework Convention on Climate Change is to be achieved Increased research is needed to quantify the probability and global and local consequences of these high impact scenarios

Climate change: an Australian guide to the science and potential impacts

Summary Offsets (also known as mitigation banks, compensatory habitat, set-asides) is a policy instrument recently introduced in several States in Australia to permit some land clearing while striving for no net loss in the extent and condition of native vegetation overall. Offsetting is criticized with respect to the amount of gain required to compensate for losses from clearing, the equivalence of losses and gains, the time lag between losses and gains and a poor record of compliance. Despite these criticisms, we conclude that offsetting is a useful policy instrument while governments continue to permit some clearing of native vegetation. However, offsets will only contribute to no net loss if (i) clearing is restricted to vegetation that is simplified enough so that its functions can be restored elsewhere with confidence or clearing is restricted to vegetation that is unlikely to persist and is not practicable to restore irrespective of clearing; (ii) any temporary loss in habitat between clearing and the maturation of an offset, or differences between the habitat lost from clearing and gained through an offset, does not represent significant risk to a species, population or ecosystem process; (iii) there will be gains of sufficient magnitude on the offset site to compensate for losses from clearing; (iv) best practice adaptive management is applied to offsets; (v) offsets are in place for at least the same duration as the impacts from clearing; and (vi) there is adequate compliance. Land clearing with offsets outside these parameters is inconsistent with ‘no net loss’.

Offsets for land clearing: No net loss or the tail wagging the dog?

Offsets, first formalised in the United States of America in the 1970s for wetland mitigation, are now widely used globally with the aim to mitigate loss of biodiversity due to development. Embracing biodiversity offsets is one method of governments to meet their commitments under the Millennium Development Goals and the Convention on Biological Diversity. Resource extraction companies see them as a method of gaining access to land, while the community may perceive them as a way of enhancing environmental outcomes. In New South Wales, Australia, BioBanking legislation was introduced in late 2006 with the aim of ‘no net loss’ of biodiversity associated with development, particularly expanding urban and coastal development. The strengths of the legislation are that it aims to enhance threatened species conservation, and raise the profile of conservation of threatened species and habitats. Weaknesses include (1) the narrowness of the definition of biodiversity; (2) the concepts are based on a flawed logic and immature, imprecise and complex science which results in difficulties in determining biodiversity values; (3) likely problems with management and compliance; and (4) an overall lack of resources for implementation and long-term monitoring. It is concluded that the legislation is a concerted effort to deal with biodiversity loss, however, stakeholders have concerns with the process, and it is unworkable with the complexity of such ecosystems (compared for example to carbon credit trading), and underdeveloped disciplines such as restoration biology and ecology. Despite these criticisms, there is a need for all stakeholders to work to improve the outcomes.

BioBanking : an environmental scientist's view of the role of biodiversity banking offsets in conservation

Central Asia has a land area of 5.6 × 10(6) km(2) and contains 80-90% of the world's temperate deserts. Yet it is one of the least characterized areas in the estimation of the global carbon (C) stock/balance. This study assessed the sizes and spatiotemporal patterns of C pools in Central Asia using both inventory (based on 353 biomass and 284 soil samples) and process-based modeling approaches. The results showed that the C stock in Central Asia was 31.34-34.16 Pg in the top 1-m soil with another 10.42-11.43 Pg stored in deep soil (1-3 m) of the temperate deserts. They amounted to 18-24% of the global C stock in deserts and dry shrublands. The C stock was comparable to that of the neighboring regions in Eurasia or major drylands around the world (e.g. Australia). However, 90% of Central Asia C pool was stored in soil, and the fraction was much higher than in other regions. Compared to hot deserts of the world, the temperate deserts in Central Asia had relatively high soil organic carbon density. The C stock in Central Asia is under threat from dramatic climate change. During a decadal drought between 1998 and 2008, which was possibly related to protracted La Nina episodes, the dryland lost approximately 0.46 Pg C from 1979 to 2011. The largest C losses were found in northern Kazakhstan, where annual precipitation declined at a rate of 90 mm decade(-1) . The regional C dynamics were mainly determined by changes in the vegetation C pool, and the SOC pool was stable due to the balance between reduced plant-derived C influx and inhibited respiration.

Carbon stock and its responses to climate change in Central Asia

An important component of the biological assessment of stream condition is an evaluation of the direct or indirect effects of human activities or disturbances. The concept of a ''reference condition'' is increasingly used to describe the standard or benchmark against which current condition is compared. Many individual nations, and the European Union as a whole, have codified the concept of reference condition in legislation aimed at protecting and improving the ecological condition of streams. However, the phrase ''reference condition'' has many meanings in a variety of contexts. One of the primary purposes of this paper is to bring some consistency to the use of the term. We argue the need for a ''reference condition'' term that is reserved for referring to the ''naturalness'' of the biota (structure and function) and that naturalness implies the absence of significant human disturbance or alteration. To avoid the confusion that arises when alternative definitions of reference condition are used, we propose that the original concept of reference condition be preserved in this modified form of the term: ''reference condition for biological integrity,'' or RC(BI). We further urge that these specific terms be used to refer to the concepts and methods used in individual bioassessments to characterize the expected condition to which current conditions are compared: ''minimally disturbed condition'' (MDC); ''historical condition'' (HC); ''least disturbed condition'' (LDC); and ''best attainable condition'' (BAC). We argue that each of these concepts can be narrowly defined, and each implies specific methods for estimating expectations. We also describe current methods by which these expectations are estimated including: the reference-site approach (condition at minimally or least-disturbed sites); best professional judgment; interpretation of historical condition; extrapolation of empirical models; and evaluation of ambient distributions. Because different assumptions about what constitutes reference condition will have important effects on the final classification of streams into condition classes, we urge that bioassessments be consistent in describing the definitions and methods used to set expectations.

Setting Expectations for the Ecological Condition of Streams: The Concept of Reference Condition

Peter Cullen, Tim Flannery, Ronnie Harding, Steve Morton, Hugh Possingham, Denis Saunders, Bruce Thom, John Williams, Mike Young, Peter Cosier and Leith Boully

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Blueprint for a living continent : A way forward from the Wentworth group of concerned scientists

How to guide the terrestrial carbon market to deliver multiple economic and environmental benefits

Optimising Carbon in the Australian Landscape

A new model for landscape conservation in New South Wales / the Wentworth Group of Concerned Scientists report to Premier Carr

Australia's climate is changing Australia: the state of Australia's water

Developing a standardized approach to measuring the state of biodiversity in landscapes undergoing disturbance is crucial for evaluating and comparing change across different systems, assessing ecosystem vulnerability and the impacts of destructive activities, and helping direct species recovery actions. Existing ecosystem metrics of condition fail to acknowledge that a particular community could be in multiple states, and the distribution of states could worsen or improve when impacted by a disturbance process, depending on how far the current landscape distribution of states diverges from pre-anthropogenic impact baseline conditions. We propose a way of rapidly assessing regional-scale condition in ecosystems where the distribution of age classes representing increasing time since last disturbance is suspected to have diverged from an ideal benchmark reference distribution. We develop two metrics that (1) compare the observed mean time since last disturbance with an expected mean and (2) quantify the summed shortfall of vegetation age-class frequencies relative to a reference age-class distribution of time since last disturbance. We demonstrate the condition metrics using two case studies: (1) fire in threatened southwestern Australian proteaceaous mallee-heath and (2) impacts of disturbance (fire and logging) in the critically endangered southeastern Australian mountain ash Eucalyptus regnans forest on the yellow-bellied glider Petaurus australis. We explore the effects of uncertainty in benchmark time since last disturbance, and evaluate metric sensitivity using simulated age-class distributions representing alternative ecosystems. By accounting for and penalizing too-frequent and too-rare disturbances, the summed shortfall metric is more sensitive to change than mean time since last disturbance. We find that mountain ash forest is in much poorer condition (summed shortfall 38.5 out of 100 for a 120-yr benchmark disturbance interval) than indicated merely by loss of extent (84% of vegetation remaining). Proteaceaous mallee-heath is in worse condition than indicated by loss of extent for an upper benchmark interval of 80 yr, but condition almost doubles for the minimum tolerable time since last disturbance interval of 20 yr. To fully describe ecosystem degradation, we recommend that our summed shortfall metric, focused on habitat quality and informed by biologically meaningful baselines, be added to existing condition measures focused on vegetation extent. This will improve evaluation of change in ecosystem states and enhance management of ecosystems in poor condition.

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Peter Cosier

Papers

Blueprint for a living continent : A way forward from the Wentworth group of concerned scientists

Optimising Carbon in the Australian Landscape

A new model for landscape conservation in New South Wales / the Wentworth Group of Concerned Scientists report to Premier Carr

Australia's climate is changing Australia: the state of Australia's water

Using ideal distributions of the time since habitat was disturbed to build metrics for evaluating landscape condition