This heat wave has broken thousands  of temperature records. Climate Central reported Satuday, “In many cases, records that had stood since the Dust Bowl era of the 1930s have been equaled or exceeded, and this event is likely to go down in history as one of America’s worst.”

In general, we expect the greatest number of temperature records to be set during a widespread drought. I explained why that is that the case in my Nature article last year on “The next dust bowl” (full text here):

Warming causes greater evaporation and, once the ground is dry, the Sun’s energy goes into baking the soil, leading to a further increase in air temperature. That is why, for instance, so many temperature records were set for the United States in the 1930s Dust Bowl; and why, in 2011, drought-stricken Texas saw the hottest summer ever recorded for a US state.

Why is this bad news? Because the Earth has warmed only a bit more than 1°F since the catastrophic Dust Bowl — and we are poised to warm an astounding 9-11°F this century if we stay anywhere near our current greenhouse gas emissions path.

Much as our current monster heat wave has been made worse by human activity (man-made global warming) so too was the Dust Bowl — but in that case it was bad agricultural practices. As NOAA’s  discussion of “The Dust Bowl Drought” explains:

The drought came in three waves, 1934, 1936, and 1939-40, but some regions of the High Plains experienced drought conditions for as many as eight years. The “dust bowl” effect was caused by sustained drought conditions compounded by years of land management practices that left topsoil susceptible to the forces of the wind.

For discussion of some of those land management practices, see here.

Unfortunately, while we have improved much of our land management since then, we have chosen to ignore decades of warning by climate scientists that unrestricted emissions of greenhouse gases would cause ever-worsening droughts. A 1990 Journal of Geophysical Research study, “Potential evapotranspiration and the likelihood of future drought,” projected that severe to extreme drought in the United States, then occurring every 20 years or so, could become an every-other-year phenomenon by mid-century.

Aiguo Dai of the National Center for Atmospheric Research, in his 2010 study, “Drought under global warming: a review,” had a similar conclusion. I will blog shortly on his updated findings, but here is a rough representation of where his analysis projects the PDSI [Palmer Drought Severity Index] will be soon after mid-century, again, if we don’t dramatically reverse greenhouse gas emissions trends:

The PDSI in a moderate emissions scenario soon after mid-century. In the Great Plains during the Dust Bowl, the PDSI apparently spiked very briefly to -6, but otherwise rarely exceeded -3 for the decade (see here).

Dai found that:

By the end of the century, many populated areas, including parts of the United States and much of the Mediterranean and Africa, could face readings in the range of -4 to -10. Such decadal averages would be almost unprecedented.

Whereas in the 1930s, you could certainly make a case that people didn’t know just how destructive their land management practices were. But we have been warned again and again that we face ever-worsening warming and drought conditions. Here are a few more studies:

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by Kaid Benfield, via National Resources Defense Council

For the first time in a century, America’s largest cities are growing faster than their suburbs.  An Associated Press story widely covered in the media yesterday, including in Time, said the findings from new 2011 census estimates reveal a “dramatic switch” from the previous pattern of suburban dominance.

Indeed, in our 1999 book Once There Greenfields, Don Chen, Matt Raimi and I reported that, between 1980 and the mid-1990s, suburban population had grown a staggering ten times faster than central-city population in our largest metro areas.  Between 1988 and 1996, central cities together had suffered an net outmigration of over two million people in each year, while suburbs experienced a collective net gain of between two and three million people each year.

A lot has changed since those bleak times for cities, from revitalization of declining neighborhoods to transit investment to a disaffection among suburbanites with long commutes and rising gasoline prices.  The recession and its aftermath have certainly underscored the last of those factors.  But the biggest change of all may be demographic:  the portion of the housing market claimed by families with children, the prime market for suburban living, has been shrinking at the same time as the Millennial generation, which strongly favors walkable lifestyles and urban living, has been coming of age.  Retiring baby boomers are also in many cases giving up large-lot living in favor of city life.

The AP story suggests that the shift to city living will be temporary, driven by unemployment and the reluctance of young adults to invest in the housing market.  While I have no doubt that the seriously dampened economy is part of the resurgence in rental housing (also reported in the story), the larger trends driving the central-city renaissance have been in effect since well before the recession hit.

As I have reported before, Dr. John Thomas of EPA has examined the geography of building permit issuance and found that urban core cities have been increasing their share of total regional building permits dating back to the 1990s, with a particularly strong increase between 2002 and 2007, before the recession hit.  In 15 of the 50 regions studied by Thomas, the central city’s share more than doubled between the 1990s and mid-2000s.

Even among those who are buying homes rather than renting, there is a strong preference now for close-in locations, where sales prices driven by demand have increased while those in outer suburbs have plummeted.  Where home purchase prices are still recovering, the recovery has been much stronger in inner, urban locations than in outer suburbs.

A quote in the AP story highlights the new values of the current generation of younger adults:

“’I will never live in the suburbs,’ said Jaclyn King, 28, a project director at a Denver hospital. King, who grew up in the Denver suburb of Littleton and attended Columbine High School, still remembers her parents’ 45-minute train commute to the city each day for work. She now rents a Denver house with her fiancée.

“’I just like being connected to everything down here — concerts, work, restaurants, all of it. This is where everything’s at,’ said King, who biked 6 miles to her job on a recent morning.“

The story also notes that the share of 16- to 39-year-olds with driver’s licenses has declined markedly.

Roughly 52 of the 73 US cities with population of greater than 250,000 showed faster annual growth (or slower rates of losses) in 2011 than their average growth over the last decade.  Primary cities in large metropolitan areas with populations of more than one million grew by 1.1 percent last year, compared with 0.9 percent in surrounding suburbs.  Cities switching from declines to gains included Pittsburgh and Milwaukee, both previously written off by some as “shrinking cities” because of what was perceived as irreversible decline because of the loss of manufacturing.

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by Manish Bapna and Kirsty Jenkinson, via WRI Insights

Where is the Steve Jobs of sustainability? The business leader with the big, disruptive ideas—and the force of will—to achieve for sustainable production and consumption what Apple’s visionary chief did for global technology and information?

This question springs strongly to mind after attending the Rio+20 conference.

Unlike the original Earth Summit 20 years earlier, business leaders were everywhere at Rio 2012. And with governments failing to make headway at the UN-led forum, there was much talk of businesses taking a greater lead in fixing the world’s environmental and development challenges.

Yet apart from Unilever CEO Paul Polman (who declared, “We have to bring this world back to sanity and put the greater good ahead of self-interest”), few corporate leaders at Rio appeared ready to take up the baton. While literally hundreds of business-led initiatives were announced, most were incremental rather than transformative. And there was limited evidence that CEOs recognize that the planet is on a fundamentally unsustainable course and the window for action is closing.

Sustainable Business Pathways

That said, Rio did see real progress in a few important areas for the private sector. In particular, assuming corporations follow through, it laid foundations for more sustainable business models and scalable partnerships between companies and governments.

Here are three Rio trends that demonstrate an emerging shift in business thinking and provide a platform that smart, forward-looking CEOs should look to build on:

1) Valuing Natural Assets

Meeting in the country that hosts the Amazon, global corporations launched multiple efforts to do something about their huge impact on nature. Taken together, these reflect a welcome shift in business attitudes toward accounting for the natural resources that underpin the global economy.

The Natural Capital Leadership Compact, signed by 15 global companies, urged action to properly value and maintain natural assets like clean air, clean water, forests, and other ecosystems. The Natural Capital Declaration saw similar commitments from a further 39 banks, insurers, and investors. And an additional 24 companies, worth a collective $500 billion, affirmed accounting for natural capital as a business imperative.

2) Corporate Reporting and Transparency

Although the final Rio communiqué watered down a proposed requirement for large companies to report on sustainability, it still provided a push for voluntary global disclosure of private sector impacts. Also significant was the UK deputy prime minister’s announcement at Rio that from April 2013, Britain will require publicly listed companies to fully report their greenhouse gas emissions. The UK move won public support from major companies—including Cisco, PepsiCo, and Aviva Investors—reflecting growing corporate acceptance of the need to be open about the private sector’s environmental footprint. Other countries are expected to follow suit. Read more