State of the climate in 2013

In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns around the world. This follows several years dominated by the effects of either La Niña or El Niño events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earths surface and through the troposphere. Some regions in the Southern Hemisphere had record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957. At the opposite pole, the Arctic observed its seventh warmest year since records began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year, leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during winter across Eurasia were followed by warm spring temperature anomalies, which were linked to a new record low Eurasian snow cover extent in May. Minimum sea ice extent in the Arctic was the sixth lowest since satellite observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years. Antarctica, on the other hand, had above-average sea ice extent throughout 2013, with 116 days of new daily high extent records, including a new daily maximum sea ice area of 19.57 million km2 reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013. The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt content in nearsurface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3.2 mm yr-1 over the past two decades. A portion of this trend (0.5 mm yr-1) has been attributed to natural variability associated with the Pacific decadal oscillation as well as to ongoing contributions from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (87.5 m s-1) on 7 November, the highest wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan as it made landfall over the central Philippines, an area where sea level is currently at historic highs, increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all continued to increase in 2013. As in previous years, each of these major greenhouse gases once again reached historic high concentrations. In the Arctic, carbon dioxide and methane increased at the same rate as the global increase. These increases are likely due to export from lower latitudes rather than a consequence of increases in Arctic sources, such as thawing permafrost. At Mauna Loa, Hawaii, for the first time since measurements began in 1958, the daily average mixing ratio of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th edition of the State of the Climate series. © 2014, American Meteorological Society. All rights reserved

The critical decade: extreme weather

When extreme weather events occur the Climate Commission is consistently asked questions about the link to climate change. This report unpacks our current knowledge about different types of extreme weather events: extreme temperatures, rainfall, drought, bushfires, storm surges, cyclones and storms.   Download key facts from the report. Download summary table of the report. Download quick facts for each state: New South Wales, Victoria, Queensland, South Australia, Western Australia, Tasmania, Australian Captial Territiory, Northern Territiory.   1. Climate change is already increasing the intensity and frequency of many extreme weather events, adversely affecting Australians. Extreme events occur naturally and weather records are broken from time to time. However, climate change is influencing these events and record-breaking weather is becoming more common around the world. Some Australian examples include: Heat: Extreme heat is increasing across Australia. There will still be record cold events, but hot records are now happening three times more often than cold records. Bushfire weather: Extreme fire weather has increased in many parts of Australia, including southern NSW, Victoria, Tasmania and parts of South Australia, over the last 30 years. Rainfall: Heavy rainfall has increased globally. Over the last three years Australia’s east coast has experienced several very heavy rainfall events, fuelled by record-high surface water temperatures in the adjacent seas. Drought: A long-term drying trend is affecting the southwest corner of Western Australia, which has experienced a 15% drop in rainfall since the mid-1970s. Sea-level rise: Sea level has already risen 20 cm. This means that storm surges ride on sea levels that are higher than they were a century ago, increasing the risk of flooding along Australia’s socially, economically and environmentally important coastlines. 2. Climate change is making many extreme events worse in terms of their impacts on people, property, communities and the environment. This highlights the need to take rapid, effective action on climate change.  It is crucial that communities, emergency services, health and medical services and other authorities prepare for the increases that are already occurring in the severity and frequency of many types of extreme weather. The southeast of Australia, including many of our largest population centres, stands out as being at increased risk from many extreme weather events – heatwaves, bushfires, heavy rainfall and sea-level rise. Key food-growing regions across the southeast and the southwest are likely to experience more drought in the future. Some of Australia’s iconic ecosystems are threatened by climate change. Over the past three decades the Great Barrier Reef has suffered repeated bleaching events from underwater heatwaves. The freshwater wetlands of Kakadu National Park are at risk from saltwater intrusion due to rising sea level. 3. The climate system has shifted, and is continuing to shift, changing the conditions for all weather, including extreme weather events.  Levels of greenhouse gases from the combustion of fossil fuels have increased by around 40% since the beginning of the Industrial Revolution, causing the Earth’s surface to warm significantly. All weather events are now occurring in global climate system that is warmer and moister than it was 50 years ago. This has loaded the dice towards more frequent and more severe extreme weather events. 4. There is a high risk that extreme weather events like heatwaves, heavy rainfall, bushfires and cyclones will become even more intense in Australia over the coming decades.  There is little doubt that over the next few decades changes in these extreme events will increase the risks of adverse consequences to human health, agriculture, infrastructure and the environment. Stabilising the climate is like turning around a battleship – it cannot be done immediately given its momentum. When danger is ahead you must start turning the wheel now. Any delay means that it is more and more difficult to avert the future danger. The climate system has strong momentum for further warming over the next few decades because of the greenhouse gases that have already been emitted, and those that will be emitted in future. This means that it is highly likely that extreme weather events will become even more severe in Australia over that period. 5. Only strong preventive action now and in the coming years can stabilise the climate and halt the trend of increasing extreme weather for our children and grandchildren.  Averting danger requires strong preventative action. How quickly and deeply we reduce greenhouse gas emissions will greatly influence the severity of extreme events in the future. The world is already moving to tackle climate change.  Ninety countries, representing 90% of global emissions, are committed to reducing their emissions and have programs in place to achieve this. As the 15th largest emitter in the world, Australia has an important role to play. Much more substantial action will be required if we are to stabilise the climate by the second half of the century. Globally emissions must be cut rapidly and deeply to nearly zero by 2050, with Australia playing its part. The decisions we make this decade will largely determine the severity of climate change and its influence on extreme events that our grandchildren will experience. This is the critical decade to get on with the job

Environmental Livelihood Security in Southeast Asia and Oceania: A Water-Energy-Food-Livelihoods Nexus Approach for Spatially Assessing Change

This document addresses the need for explicit inclusion of livelihoods within the environment nexus (water-energy-food security), not only responding to literature gaps but also addressing emerging dialogue from existing nexus consortia. We present the first conceptualization of ‘environmental livelihood security’, which combines the nexus perspective with sustainable livelihoods. The geographical focus of this paper is Southeast Asia and Oceania, a region currently wrought by the impacts of a changing climate. Climate change is the primary external forcing mechanism on the environmental livelihood security of communities in Southeast Asia and Oceania which, therefore, forms the applied crux of this paper. Finally, we provide a primer for using geospatial information to develop a spatial framework to enable geographical assessment of environmental livelihood security across the region. We conclude by linking the value of this research to ongoing sustainable development discussions, and for influencing policy agenda

Impacts of climate change on fisheries and aquaculture

The 2015 Paris Climate Agreement recognizes the need for effective and progressive responses to the urgent threat of climate change, through mitigation and adaptation measures, while taking into account the particular vulnerabilities of food production systems. The inclusion of adaptation measures in the fisheries and aquaculture sector is currently hampered by a widespread lack of targeted analyses of the sector's vulnerabilities to climate change and associated risks, as well as the opportunities and responses available. This report provides the most up-to-date information on the disaggregated impacts of climate change for marine and inland fisheries, and aquaculture, in the context of poverty alleviation and the differential dependency of countries on fish and fishery resources. The work is based on model projections, data analyses, as well as national, regional and basin-scale expert assessments. The results indicate that climate change will lead to significant changes in the availability and trade of fish products, with potentially important geopolitical and economic consequences, especially for those countries most dependent on the sector

[Arctic] Greenland ice sheet [in “State of the Climate in 2012”]

Melting at the surface of the Greenland Ice Sheet set new records for extent and melt index (i.e., the number of days on which melting occurred multiplied by the area where melting was detected) for the period 1979–2012, according to passive microwave observations (e.g., Tedesco 2007, 2009; Mote and Anderson 1995). Melt extent reached ~97% of the ice sheet surface during a rare, ice-sheet-wide event on 11–12 July (Fig. 5.13a; Nghiem et al. 2012). This was almost four times greater than the average melt extent for 1981–2010. The 2012 standardized melting index (SMI, defined as the melting index minus its average and divided by its standard deviation) was +2.4, almost twice the previous record of about +1.3 set in 2010