I first came to China in 1985 to study bird migration at Beidaihe, on the coast east of Beijing. There was little traffic in the town, where carts pulled by donkeys carried bricks and other loads. In Beijing, bicycles abounded, and taxis were rare.
Though cars were yet to throng the roads, the environment was not pristine. Thanks in large part to coal being burned for power and heating, a haze of smog sometimes settled over the land. Indeed, China was already facing serious issues such as pollution, deforestation, erosion and loss of wildlife, which were detailed in The Bad Earth: Environmental Degradation in China by US-based geographer Vaclav Smil.
Published in 1983, The Bad Earth was a pioneering work, drawing on a multitude of sources including Chinese scientists' reports and newspaper items. It was criticised within China and by some Western scholars, who suggested Smil overstated the problems. But he was soon vindicated as prominent officials expressed serious concerns.
Although much has since been said and written about the need for China to reverse its environmental decline, recent years have abounded with news reports telling of the nation's earth lurching from bad to terrible.
This environmental decline has occurred as the economy has grown at an astonishing pace, guided partly by officials believing it possible to develop first and clean up some time later.
Which isn't to say there have been no clean-up attempts. There have been many, some more effective than others.
During a return visit to Beidaihe in 2009, I headed to a stretch of coastline south of the town that I formerly knew as seemingly remote, with rice paddies fringing the shore. The area had been transformed. There were factories and refineries and smoking chimneys, and trucks shuttling back and forth along a rutted muddy track, as construction of more plants proceeded. At least some of these plants had been relocated from Beijing as the capital prepared for the Olympics held the previous year. So Beijing had cleaned up a little, by simply moving polluting industries.
Wildlife was of course caught up in the widespread carnage. There were high-profile conservation efforts, such as for the giant panda - with China setting aside forests that could have been logged for timber. The panda was among species classed as "living national treasures". Others included the baiji, a small dolphin unique to the Yangzte River. But the baiji wasn't treasured enough, for by 2007 it was declared functionally extinct - meaning a few individuals just might survive, but the species had no future.
In October last year, The Economist published a bleak assessment of China's water crisis, noting that a gigantic engineering "solution" - diverting water from the Yangzte north to the Yellow River - is already having serious environmental repercussions.
While a far smaller river in Shanghai turned bright blue in January, and had previously turned yellow or black from factory discharges, the most visible recent sign of pollution has been the smog that has hit headlines.
You've surely read terms like "airpocalypse". A commentary in The Lancet by authors including former health minister Chen Zhu noted: "Studies by the World Bank, WHO and the Chinese Academy for Environmental Planning on the effect of air pollution on health concluded that between 350,000 and 500,000 people die prematurely each year as a result of outdoor air pollution in China."
Last month came reports that the smog blanketing much of eastern China filters out so much sunlight that crop growth is stunted. According to He Dongxian , an associate professor at China Agricultural University's College of Water Resources and Civil Engineering, Chinese agriculture may even suffer conditions "somewhat similar to a nuclear winter".
Importantly, China's environmental problems are not China's alone. There was perhaps some shock in the US recently, with a report that China's air pollution significantly affects the west coast. But China is also like a global factory, and around a fifth of its export-related emissions arise from exports to the US. Global consumers favour low-priced goods, but these come with environmental costs.
There may be cause for optimism in China's fast development of renewable energy. But don't celebrate just yet. In January, Armond Cohen, co-founder of the US-based Clean Air Task Force, cautioned that new fossil energy output in China exceeded new wind energy by six times and solar by 27 times. China has plans for reducing coal burning in and around cities that seem as monumentally misguided as the South-North Water Diversion Project. The Inside Climate News team has reported on construction of "coal bases" in far-flung regions, where coal will be used to make synthetic natural gas. The largest of these spans an area of around 400 square miles - almost as large as the entire Hong Kong SAR.
The coal bases guzzle water in already arid environments. Plus, they look set to cause mind-boggling greenhouse gas emissions.
Like the water transfer, the coal bases seem the product of an engineering mindset prevailing in China, rather as it does in Hong Kong. Yet China is also steeped in wisdom and the concept of harmony with nature. It's past time to act according to such wisdom. As Taoist philosopher Lao Tzu cautioned: "Stretch a bow to the full, and you will wish that you had stopped in time."
Martin Williams, PhD, is a Hong Kong-based writer specialising in conservation and the environment