In a recent article [Journal of Pacific Archaeology, vol 1(2), 2010], Scott Fitzpatrick contends that the AD 1300 event model is unhelpful as a key to understanding environmental and societal change in the Pacific during the past 1500 years. We reject this contention on the grounds that there are ample and persuasive grounds for supposing otherwise. The AD 1300 event model proposes that climate change (especially cooling) and sea-level fall affected most of the Pacific Basin during the transition between the Medieval Warm Period and Little Ice Age, and that the impacts of these changes on food resources were so profound that they led to enduring impacts on human societies in this region, particularly Pacific Islands. We aver that the AD 1300 event model remains a powerful tool for understanding last-millennium environmental and societal change in the Pacific Islands and that all the charges Fitzpatrick levels against it can be readily dismissed.

The comment by Hall and Sanders raises some issues we are able to clarify. These authors also criticize our study for its omissions, something we regard as inevitable in a one-off study of this nature. We contend that neither of these concerns invalidate our study's conclusions. Hall and Sanders's first criticism concerns sampling and interpretation and is prefaced by the rhetorical question "of whom can the authors legitimately speak?" At the time of the study, both authors had interacted with both communities in the Rewa Delta for more than 20 years, each author speaking one of their two vernacular languages (Fiji Hindi and Bauan-Fijian) and being intimate with their cultural mores, attributes that allowed us privileged access to these communities for the purpose of the study. Interviewee selection was not "haphazard". In both study sites, we were constrained in this by gender, age, language, relatedness, status, and religious affiliation, all of which affected our ability to freely speak to those we might have targeted had we not been so encumbered yet we are satisfied that the 64 people we interviewed (selected by age, gender and residence time) represented a cross-section of the target population in each community. Full details of interviewees are given in Lata's MSc thesis (Lata 2010), which was referenced several times in our paper (Lata and Nunn 2012). We are indeed somewhat "startled" that Hall and Sanders overlooked this. A requirement that potential interviewees must have been continuously resident in our sample locations for 30 years is not "troubling" to us. We used a 30-year figure because (1) our experience of gathering environmental-change data from Pacific Island communities suggests that this was the optimal period needed to comprehensively exclude persons who might give misleading information2 and (2) flood data in particular suggest that this is the period within which recent climate-change effects are detectable, something on which we sought to allow our informants to comment. As we explain in our paper, "although the specific data analysed in this paper were obtained from individual interviews, these were supplemented by focus-group discussions in appropriate cultural situations for the purposes of understanding both the broader context and canvassing group views" (Lata and Nunn 2012: 174).

As in the past, most Pacific Island people live today along island coasts and subsist largely on foods available both onshore and offshore. On at least two occasions in the 3500 years that Pacific Islands have been settled, sea level changes affected coastal bioproductivity to the extent that island societies were transformed in consequence. Over the past 200 years, sea level has been rising along most Pacific Island coasts causing loss of productive land through direct inundation (flooding), shoreline erosion and groundwater salinization. Responses have been largely uninformed, many unsuccessful. By the year 2100, sea level may be 1.2 m higher than today. Together with other climate-linked changes and unsustainable human pressures on coastal zones, this will pose huge challenges for livelihoods. There is an urgent need for effective and sustainable adaptation of livelihoods to prepare for future sea level rise in the Pacific Islands region. There are also lessons to be learned from past failures, including the need for adaptive solutions that are environmentally and culturally appropriate, and those which appropriate decision makers are empowered to design and implement. Around the middle of the twenty-first century, traditional coastal livelihoods are likely to be difficult to sustain, so people in the region will need alternative food production systems. Within the next 20-30 years, it is likely that many coastal settlements will need to be relocated, partly or wholly. There are advantages in anticipating these needs and planning for them sooner rather than later. In many ways, the historical and modern Pacific will end within the next few decades. There will be fundamental irreversible changes in island geography, settlement patterns, subsistence systems, societies and economic development, forced by sea level rise and other factors.