This column by John Mott-Smith, a member of Cool Davis, is cross-posted from the Davis Enterprise. The last column was about bad news from the Intergovernmental Panel on Climate Change. They issued three reports recently.

Last September, the first report made the point that scientists are 95 percent or greater certain that global warming is being driven by human actions. In the scientific community, 95 percent is essentially 100 but leaving room for unexpected new information.

The second in the series was gloomy, even alarming, basically saying things are worse than we thought; adverse effects are not in some far-off future but are rather underway now. The third report, although it echoes the warning in the earlier reports, made two findings that can be considered good news, or at least a silver lining.

One, if governments get their act together, there is still time to avoid the worst effects of climate change but it is going to take dramatic changes in policy and practice, as well as cooperation among nations. Two, there is evidence that people and nations around the planet are beginning to take the issue seriously. Particularly at the local government level, there appears to be a growing understanding that action is needed.

Good news indeed, but not, at this point, enough to keep carbon dioxide levels in the atmosphere from increasing at an accelerating rate.

This column is about some of the stories in the news of late that seem to offer hope that if governments face up to the problem — including the scope of changes required — there are some promising technologies that may be a part of the solution.

Energy efficiency continues to be the least expensive and most effective way of reducing greenhouse gases emitted as a by-product of producing electricity, and one action everyone has been encouraged to take is to switch out incandescent light bulbs and replace them with more efficient CFLs or the even more efficient LEDs.

The good news is that LED efficiency (light output per unit of energy consumed) is increasing and is expected to quadruple in the next 15 years, while the cost of purchasing LED bulbs is expected to plunge over the same time frame to a level at or below the current cost of an incandescent bulb.

More good news: This one not yet ready for prime time (commercial application), but it’s very promising. Photovoltaic panels are generally able to convert about 20 percent of incoming light into electricity. This relatively low level of conversion is apparently due to current systems utilizing only a portion of available wavelengths.

German researchers, however, have demonstrated solar panels that, by capturing a broader slice of the incoming light, have been able to achieve nearly 50 percent conversion efficiency. This development, if cost-effective when produced at scale, could have a huge effect on production of clean, renewable energy.

No matter how efficient we become, we won’t get where we want to go in terms of emission reductions without significant increases in renewable power, coupled, of course, to decreases in electricity produced from fossil fuels..

Also encouraging is news from the South Central Valley of a technology that uses the sun to recycle (or re-use) irrigation water. The state has estimated that about 20 percent of total electricity use in California is in one way or another associated with providing water for homes, businesses and agriculture. The Water FX system produces clean water at about one-fourth the cost of water produced by the more conventional reverse-osmosis desalinization process.

Essentially, the system acts similar to a still — using energy from the sun to separate out the salts, minerals and contaminants accumulated during irrigation and producing clean water to be used again for irrigating crops. The system has been in test-phase operation for more than a year, producing about 14,000 gallons a day, and operators plan to increase that to 2 million gallons a day within a year, and 20 million within five years.

According to the operators, the system is “sustainable, scalable and affordable.”

Finally, at least as far as this column is concerned, is the potential to recycle all plastic into usable materials. This is not theoretical. A chemical engineer-turned-entrepreneur is operating plants in three countries that process more than a million pounds a day of all different kinds of plastics and separate that mess into distinct piles that are 99 percent pure. These are then commercially valuable. The good news is that his process requires only 10 percent of the energy required to produce virgin plastic.

According to a recent article about this process, the world uses 24,000 plastic bags every second of every day, a million plastic cups are used every six hours to provide drinks to people on airplanes, and more than a million tons of plastic is discarded every year. The problem is access to a reliable supply of plastic.

Few countries require that plastics (especially from electronic devices such as computers, printers and fax machines) be recycled. Although initially located in the United States, this engineer/entrepreneur took his business to Europe because Europeans recycle roughly 2.5 times the amount of plastic as the we do in this country, thereby providing a steady stream of material.