Climate change: The reality of now in Victoria

The Great CO2 Enhancement Experiment (~40% and rising!) continues unabated, and looks set to continue for the foreseeable future. Unfortunately, the results are coming in, and the verdict doesn't look good. Numerous lines of evidence from around the globe (as presented previously at planet doom?) support the idea that this is the case.

A recent jaunt across country Victoria prompted some reflection on the effects of climate change closer to home. Much of Australia, the southeastern corner in particular, is experiencing a long-term drought. In Melbourne, the drought is of 'unprecedented severity' – annual rainfall has been below average for 12 consecutive years. And the drought continues, with record-low monthly rain in September, and very little rain thus far in October.

Drought is a regular climatic event in this part of Australia, often corresponding with ENSO – El Nino years are dry, while La Nina years typically bring relief. Unfortunately, the recent La Nina brought little precipitation to the region. This may in part be related to the unprecedented events observed in the Indian Ocean; a third consecutive positive Indian Ocean Dipole (and apart from El Nino two years in a row, too). Historically, the positive IOD does show a negative relation with rainfall over this part of the continent.

The impacts of the drought are widespread, with concerns continuing to grow over the availability of water resources. The Murray-Darling river system -- southeastern Australia's lifeline – is a particular concern. For a third year running, very little water has been made available for irrigation along the river (also reported last year), with zero allocation in some parts. Nearly 90% of the wetlands in the MD Basin have disappeared. These effects are being exacerbated by human mis-management, with individual states acting on an ad-hoc basis.

Similar impacts are seen throughout Victoria. For much of the state, streamflows in the rivers are currently running below 10% of capacity. In total, water storage across the state is at 22% of capacity. Melbourne, a city of over 3m people, is slightly better off with storage levels at 34%. Water restrictions are in place..

Another consequence of the drought is the threat of wildfire becomes larger. In the current environment, the forested areas of Victoria are a particular are of concern for the upcoming summer. The water catchment areas of Melbourne are a concern; a major bushfire is these regions could increase the difficulty of maintaining an adequate water supply for the future.

The current drought is unprecedented in Australia's recorded history (over 100 years). This is climate change, part of the growing climate instabilities being observed around the globe. An enhancement (a corruption!) of the natural variability. The hysteresis in the Earth system means the effects, from causes long past, are only now becoming apparent. And the causes (i.e. CO2 radiative forcing) continue today, meaning that these events and their impacts are but a foretaste of our future.

Australia and Victoria are among the first -- by no means the last -- to confront the new realities of climate change. Adaptation will be a long, difficult process. Water – vital to human life -- is but one issue among many. Understanding how climate and the hydrologic cycle interact is crucial for the future. As Australian federal and state governments try to manage the current water crisis, the globe will be watching to learn from both our mistakes and successes. Adaptation is an unknown challenge and recent events provide an opportunity to lead the world towards a brighter, greener future.

In both a local and global sense, the time to act is now. Inaction is not an option. Society must adapt to the immediate realities and simultaneously try to minimize future impacts, through both emissions reductions and the development of a less environmentally intense lifestyle. We owe a moral obligation to future generations to accomplish this, a Green New Deal for the 21^st century.

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Images: 1. Low water levels in Thomson Dam via The Age
2. A nice gum tree in Lake Eildon NP, by me

Myanmar flooding from cyclone Nargis

Cyclone Nargis struck Myanmar (Burma) on 2 May 2008. Current NASA MODIS imagery and news reports indicate that this cyclone is an emerging humanitarian disaster.

From an informative Terra Daily news item:

At least 351 people were killed and nearly 100,000 left homeless when tropical cyclone Nargis tore through Myanmar, razing thousands of buildings and knocking out power lines, state media said Sunday.

The meteorological stats of the storm, as gleaned from the news item above...

Nargis made landfall late Friday around the mouth of the Ayeyawaddy (Irrawaddy) river, about 220 kilometres (137 miles) southwest of Yangon, before hitting the country's economic hub...

Electricity supplies and telecommunications in Yangon have been cut since late Friday night as the storm bore down from the Bay of Bengal, packing winds of 190-240 kilometres (120-150 miles) per hour.

These stats put it at the borderline Cat-3/Cat-4, suggesting a storm surge of ~4 m.

The image is a before-and-after comparison of the Ayeyawaddy province of Myanmar.Spatial dimensions of the images are 400x225 km. Yangon (nee Rangoon) is towards the upper right corner. The picture is a false-color image, comprised of visible and short-IR channels. Water appears black here; sediments in the water are dark blue (see here for description). The top panel is from 26 April; the bottom from 5 May, three days after the storm. Judging from the imagery, the area is largely low-lying river delta.

With the aid of this satellite image with the track superimposed, the storm presumably came ashore in the lower left of the image, near the large river. Comparison of the two images suggest the storm surge has been quite extensive. A swath of water is apparent across the peninsula (the storm track, perhaps?). Extended regions of the delta system are underwater –- new islands have formed off the new coastline, albeit temporarily.

The water over the former land is a deep blue hue, suggesting lots of erosion and silt transport out to sea.

Careful examination (and guesswork on the navigation!) indicate that the flood waters are very close to Yangon, as well. This is consistent with this statement (from the above news article): “There are also fears that the poorer outlying areas of Yangon, with their flimsy houses, might have been hard hit.”

An as-I-write post at The Intersection is indicating that up to 10 000 may be dead, and the normally reclusive government is appealing for international aid. These rare appeals, supported by the remote sensing data, would suggest that indeed they were hard hit.

Addendum: From Dr Jeff Masters' WunderBlog:

The storm hit the coast of Myanmar Friday night as borderline Category 3/Category 4 cyclone, with winds of 130-135 mph. After passing over the low-lying and densely populated Irrawaddy River delta region, Nargis made a direct hit on the capital city of Rangoon (Yangon), as a Category 1 storm with top winds of 80 mph...

However, it was the storm surge, not the winds, that was the big killer in Nargis. The storm tracked over the low-lying Irrawaddy River delta region, which is highly vulnerable to storm surge deaths due to its low elevation, dense population, and limited hurricane awareness of the people. I could find no records of a major tropical cyclone ever making a direct hit on the Irrawaddy River delta.

Again, as suggested by the imagery.

Addendum 2: Here is the official NASA Natural Hazards version of the picture above. They use a different 'before' picture, and their fancy image processing software and GIS make their image a bit crisper. Here is a MODIS true-color image of the cyclone at landfall.

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Image: compiled by me, from raw material collected at NASA MODIS Rapid Response

'Roof of the World" falling in

Tibet, a Plateau region in central Asia, is a region facing many problems. Besides having its culture overrun by China in the 1950s, the “roof of the world” has a host of environmental issues to contend with, many wrought by encroaching climate change.

Tibet was covered in tall cypress trees 4600 years ago but today is mainly a desert pasture. Tibet's spiritual leader-in-exile, the Dalai Lama, seems to imply that this is due to corrupt Chinese officials. They may very well be exacerbating the trend, but Tibet has been largely deforested for a long time, a result of clearing primarily to accommodate crops and livestock.

The average of altitude of Tibet is over 4900 m, and the region is mountainous. There are many glaciers in the region, with more being discovered all the time. As is the trend worldwide, many of the glaciers are shrinking. Over the past 100 years, the area covered by glaciers in the area has shrunk by an estimated 30%. The Tibetan Plateau is the source of of many of China's major rivers. As the glaciers there melt away, China's future water supply comes under threat.

As with the deforestation issue above, attribution of the source of this is somewhat politicized. The Chinese government hypothesizes that climate change is driving much of this. Tibetan activists place much of the blame on China's environmental policies. In reality, it is not likely an either/or situation, but rather a combination of both. That Mt Everest, the world's tallest mountain (which is not entirely within China's control), is undergoing significant melting (see image pair -- same site, 1968 on top, 2007 below), would suggest that climate change is driving much of this. Still, humans can have a large impact on the climate through land use changes...

Other evidence also suggests climate change. Temperatures in Tibet are rising at a rate about twice the global average, about 0.3 C per decade. This is consistent with other elevated regions of the world. The region has also been facing something of a drought, which is of course not a sign of climate change by itself. Still, much of the region has seen record-low humidity over the past few months, and parts of Tibet have seen 'Exceptional' levels of drought (see here for interactive global map). These observations are consistent with accelerating climate change around the globe. The Chinese are resorting to the creation of artificial snow, a first for the region in order to alleviate the extended dryer-than-normal conditions.

The impacts of climate change in Tibet have serious implications for the globe. Millions of people rely on the rivers which begin in this region for drinking water and irrigation. As a whole, China has been observing many impacts of climate change during the course of this year, from increasing desertification to extreme floods. Attempts to stabilize the flow of the Yangtze river (which incidentally originates in Tibet) with the Three Gorges dam have not been going well to date; the dam is creating more environmental problems than anticipated. If not effectively managed, these events create the possibility for future humanitarian crises (like food shortages), which in our increasingly volatile world can create the triggers for larger conflagrations.

Such a possible future highlights the need for effective action in adapting to and mitigating against climate change. The western nations need to show leadership at the upcoming Bali climate talks, rather than bickering and finger-pointing. Assigning blame is a pointless exercise. It may be too late to avoid some problems, but giving up and doing nothing insures that the worse will happen.

River impacts

In this post from planet doom?, the possibility of enhanced flooding along rivers due changes in water uptake from vegetation was briefly noted. In general, rivers face many dangers from both our current environmental management practices and climate change. A few recent items below highlight these threats.

A new study suggests that many rivers impacted by dams or extensive development will require significant management interventions to protect ecosystems and people, Because of the changes in the flow of rivers globally wrought by damming and/or development, most have a diminished capacity to adjust to the changes expected with global warming.

The changes to river systems are expected to vary -- some are expected to have large increases in flood flows while other basins will experience water stress such that there is not enough water to meet human needs. For example, by the 2050's, mean annual river discharge is expected to increase by about 20 percent in the Potomac and Hudson River basins but to decrease by about 20 percent in Oregon's Klamath River and California's Sacramento River

Recent news items demonstrate some negative effects of human 'management' of river systems, even before we have felt the full brunt of climate change. This news article reports that 15 000 wildebeest dies while crossing the Mara river in Kenya. Such a mass death was the first of its king in recent memory. Many of the animals died as a result of being trampled. Some officials blame the destruction of the nearby Mau forest for changing weather patterns and affecting tide levels, and they called on the government to curb the deforestation.

The Three Gorges dam in China is also proving to be an 'ecological disaster', even before it is fully completed. The water quality of the Yangtze's tributaries is deteriorating rapidly, as the dammed river is less able to disperse pollutants effectively. The incidence of algae blooms have risen steadily since the reservoir was completed in 2006. The rising water is also causing rampant soil erosion, resulting in riverbank collapses and landslides along the shores of the Yangtze's tributaries.

These events illustrate examples of the dangerous secondary effects we have seen with our current environmental degradation. Climate change will likely exacerbate these effects. The inter-linkages within the biosphere means that even relatively simple alterations to the environment are likely to have unforeseen consequences. Great care is required if we want to avoid the worst follow-on effects. This especially applies to climate change, about which we are woefully ignorant and arrogantly overconfident -- a dangerous combination. The time is now for prudent action to (try to) pull back from the brink of dangerous climate change, before it is too late for future generations.