The hot topic of the day, literally, is the weather and how it's changing.

Summers are generally hotter, winters are colder, and for the foreseeable future climate change will affect a lot of people around the world, mainly for the worse.

That's because contingency plans are expensive and many of the world's economies are shaky. And in many areas of the world, solving problems associated with climate change was never part of many industries' budget considerations.

One of these is the wine industry, where some curious things are happening.

For one thing, regions once considered cold climates for the growing of grapes are now seen not as cold but as moderate. And this has changed the way wine is made.

One example would be East Coast and Midwest states, where consumers are seeing some of the best wines the wineries have ever made. Wines from Ohio, Michigan, Virginia, New York and Pennsylvania are now being compared with some of the best wines in America.

Another example is California's Carneros, a once-cool area in southern Napa and Sonoma counties that has a lot of cool-climate grapes, notably chardonnay and pinot noir.

In the last decade, we have seen ripeness levels rise in these wines, and though they remain substantially similar to past years in terms of style, we have seen many wines rise in alcohol, due in part to the rise in average temperatures.

The same goes for such cooler regions as Santa Lucia Highlands in Monterey County, southern San Luis Obispo County, Santa Rita hill in Santa Barbara, and the western Russian River.

But consumers of California wine are now getting a taste of the past with the recent releases of wines from the cool 2010 and 2011 vintages.

Both years were atypically cool — possibly also linked to global climate change. So cool, in fact, that some producers say they had to take extreme measures to make good wines.

Though they were different years, both had summers that essentially never had the expected high temperatures that winemakers rely on for full ripeness. In 2010, some vineyard managers panicked and did things to the vines that made for more erratic wines than might have been produced.

Some were excellent, some were not.

In 2011, it was simply a cool summer, but the learning experiences from the prior year and other factors helped to make some stellar wines. In general, it was a superb year for balanced wines.

In 2010 and 2011, some California winemakers were worried that they would get flavors they feared consumers wouldn't like. Many ended up resorting to treating their red grapes at the state's few flash d?ente providers.

The flash d?ente system, developed in France in the 1990s, treats red grapes in a way that gives them better color and removes elements winemakers don't like to display.

In general, 2010 and 2011 wines are better structured than some years in the early 2000s, in which acids were noticeably lower.

Wine of the Week: 2011 Y. Rousseau Old Vines Colombard, Russian River Valley ($18): This brilliant white wine is made from a grape that rarely gets the respect it deserves. This wine's striking aroma is a bit like lime zest, juniper and tangerine.

The wine reminds me of biting into a Granny Smith apple. Its dry nature makes it perfect to pair with any lighter food. And the acidity is due in part to the terrific 2011 vintage.

Dan Berger lives in Sonoma County, where he publishes "Vintage Experiences," a weekly wine newsletter. Write to him at winenut@gmail.com.