Addressing water issues across the water cycle is key to adapting to climate change.
COP21 will be remembered for the historic Paris Agreement that saw an important step towards global action on climate change. For observers of this year's global gathering in Bonn, I recommend keeping an eye on discussions about water resilience.
Too little or too much - climate change will be felt most through its impact on the water cycle. I'm at COP23 to work with colleagues from around the world to continue to push for water to become an even greater priority.
Addressing water issues across the water cycle is key to adapting to climate change and reducing the impact of water-related disasters.
Voice the vulnerabilities
Climate change increases the intensity and frequency of natural disasters and water-related crises, including unpredictable rainfall, floods and droughts.
In addition, water is critical to successful climate change mitigation, since many efforts to reduce greenhouse gas emissions depend on reliable access to water resources.
Governments must make water figure prominently within their Nationally Determined Contributions, their National Adaptation Plans and other UNFCCC programs and mechanisms.
It is significant that Fiji is presiding over the 23rd session of the COP being held in Bonn. Fiji is the first Small Island Developing State (SIDS) to assume the Presidency of the UNFCCC COP process.
This represents an opportunity to voice the vulnerabilities and challenges facing SIDS and other low-lying coastal areas.
It is crucial for the world to fully realize that the climate is changing around the world, although not at the same rate.
For example, sea level rise in areas of the Pacific Ocean is currently four times the global average, coupled with enhanced storm-surge, this is potentially devastating.
Many atolls, homes to thousands, are less than five metres above sea level. The changing climate may have a catastrophic effect on such local communities, damaging their physical environment, customs and culture.
To help decision makers understand the impact, Arup has developed a resilience index to focus action and support on improving the resilience of low lying Pacific Island Nations to sea level rise.
Most Pacific islands are already suffering from the impact of climate change on communities, infrastructure, water supply, ecosystems, food security and human health.
Rising sea levels and enhanced storm surges are an immediate existential threat. Five low-lying Solomon Island archipelagos have already been submerged.
Understanding the potential impact on communities and livelihoods is essential to building resilience for the islands. In the words of Enele Sosene Sopoange, Prime Minister of Tuvalu, "If we save Tuvalu, we save the world".
Cities around the world also need to adapt to changes across the water cycle. At Water Action Day, I'll be joining a panel discussing the responsibility cities have in developing the world's resilience to the impacts of climate change.
Because of the rapid expansion of cities, water resources are already under increasing stress. Moreover, local authorities need to safeguard their citizens from climate-related risks, arising from either too much, too little or contaminated water, and build-in greater resilience.
Investing in both infrastructure and capacity development to improve access to safe drinking water and sanitation and increase water-related disaster preparedness will lead to healthier and more prosperous communities.
It will enable cities to bounce back more quickly and cope better when disaster does strike. However, national and local governments need to enhance their collaboration to implement national climate and water policies on the ground, closest to where water can be effectively managed.
Looking through a climate change lens at the Pacific Island Nations we can appreciate how this global challenge will be felt locally, how communities and cultures are facing overwhelming odds and how we need to build momentum in our global action to do something about it.
Mark Fletcher is global water leader at Arup, an independent firm of designers, planners, engineers, consultants and technical specialists, working across every aspect of today’s built environment.