Water Journal : Water Journal May 2014
MAY 2014 WATER 35 Feature Article Climate change is already having a major impact on the planet, with impacts forecast to worsen signi cantly, according to the latest summary of peer-reviewed climate science from the Intergovernmental Panel on Climate Change (IPCC). But the risks of climate change can be alleviated with adaptation. While some sectors and regions may bene t from low levels of warming, negative impacts will outweigh positive ones, the report says. Greater impacts will be seen at higher levels of warming. But strong mitigation now could signi cantly reduce the risk of severe climate impacts. The report, Climate Change 2014: Impacts, Adaptation and Vulnerabilities, was released recently in Yokohama, Japan. Dr Chris Field, co-chair of the report, said the amount of research on climate impacts had doubled between 2005 and 2010. The report assesses current climate impacts, future climate risks and adaptation potential across sectors including the economy, health, agriculture and security. KEY FINDINGS Global income could fall by 0.2--2% in response to a global average temperature increase of 2°C, with worse losses "more likely than not" according to the report, although it adds that economic forecasts are fraught with dif culties. While some studies predict crop production will rise, most suggest major crop production (wheat, rice and maize) will fall with 2°C warming, with increased variability between years. More people will be displaced by climate impacts such as rising seas, but the report says there is low con dence in estimates of how many people will be affected. There is medium con dence that climate change has already played an indirect role in recent con ict and civil wars, and will increase national security threats in the future. Climate change will exacerbate health problems up to 2050, and post-2050 is likely to increase ill health. Deaths have already risen thanks to extreme heat, although there may have been some fall in deaths from extreme cold. The tropical and subtropical regions will see more frequent drought and, globally, water quality is expected to decline. Climate impacts will disproportionately affect developing nations and people in poverty, although climate change has already been felt across the globe. The report also summarises impacts already seen, mostly in the natural world. Glaciers and permafrost are melting, and scientists have documented shifts in species distributions. Many countries have already taken steps to develop adaptation plans, the report says, which could signi cantly reduce further climate risks. Climate Change 2014: Impacts, Adaptation and Vulnerabilities is the second of three reports to make up the IPCC Fifth Assessment Report. The rst, The Physical Science Basis, was released in September 2013. The nal part, Mitigation of Climate Change, will be released shortly, with the compiled report due in late 2014. The Conversation author and climate scientist at Victoria University, Roger Jones, was at the report meetings in Yokohama. A coordinating author on the report, he asked fellow authors what they thought was the key message. Their responses follow: Roger Jones, Victoria University: Coordinating Author, 'Foundations of Decision-Making' The last Working Group II report talked mainly about the impacts of climate change; particularly, how risks increase at higher levels of warming. While the analysis of key risks is repeated with new data, adaptation is a big feature of this report. The capacity to adapt is looked at across regions, sectors and key risks. The limits to adaptation are assessed but poorly known. Some of these limits may be reached at 2°C warming above pre-industrial levels. At 4°C above these levels, and accounting for adaptation, key risks are high across the board. The global costs of impacts are incomplete with uncertainty pointing towards higher levels than is currently quanti ed. The costs of adaptation are unknown, but the bene ts of undertraining adaptation are recognised. Current levels of impacts and the adaptation needed to respond to these point to the need for prompt and ongoing action on climate change if future risks are going to be adequately managed, irrespective of future levels of mitigation. Saleemul Huq, International Institute for Environment and Development: Coordinating Author, 'Adaptation Needs and Options' As a lead author on adaptation in the third, fourth and now fth assessment reports, I have seen the evolution of the topic's treatment from a single chapter in the third report, to one-and-a-half chapters in the fourth, to four chapters in the fth. This represented the demand for information from governments (who make up the IPCC and provide the outline of topics that the scientists are then asked to write about). The Fifth Assessment was able to provide much more information on planning adaptation, but less on actual implementation of adaptation plans. This illustrates both the explosion in adaptation plans and actions around the world and also the limitations of the IPCC's strict restrictions on relying on the peer-reviewed scienti c literature and avoiding other sources of information. TIME TO ADAPT: COSTS OF CLIMATE CHANGE MOUNTING James Whitmore and Michael Hopkin, editors at online news and commentary site The Conversation, provide an 'expert wrap' on the latest IPCC Report.
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