In this 2010 file photo, a UA graduate student help count buds and blooms on a marked cholla bush on Tumamoc Hill as part of climate change research.

Like the rest of the world, Arizona faces a long list of challenges in trying to cut greenhouse gas emissions enough to keep temperatures from spiraling out of control, says a University of Arizona scientist who helped write a new international report on climate change.

But hot, dry Arizona, long considered “ground zero” for climate change impacts, also has a lot of advantages compared to other U.S. states, said Diana Liverman, regents’ professor and acting director of UA’s School of Geography and Development. Most obviously, while our temperatures have grown hotter faster than many or most other U.S. states, our sunny climate gives us an advantage with solar energy, she said.

Liverman was one of 60 scientists around the world and six from the U.S. who just co-authored a new report from the International Panel on Climate Change, the United Nations body that has been studying the impacts of climate change around the globe for a generation. She was a lead author for the report’s chapter on achieving sustainable development, eradicating poverty and reducing inequality.

Released Sunday night, the report warns that an unprecedented array of social, technological and lifestyle changes are needed to reduce greenhouse gas emissions enough to meet global goals of limiting future temperature increases to no more than 1.5 degrees Celsius or 2.7 degrees Fahrenheit above preindustrial levels.

The world needs “rapid and far-reaching transitions in energy, land, urban and infrastructure, (including transportation and buildings), and industrial systems,” the report said. Annual carbon dioxide pollution levels that are still rising now must drop by about half by 2030 and to near zero by 2050.

The measures nations committed to in the December 2015 Paris Climate Accord are inadequate to keep temperatures from rising 2 degrees Celsius, or 3.6 degrees Fahrenheit, the report said.

The commitments made at that accord — which President Trump has since announced his intention to leave — could raise global temperatures by more than 3 degrees Celsius by 2100, Liverman said. Because land warms more than oceans, this could raise Arizona temperatures by 4.7 degrees Celsius or 7 degrees Fahrenheit by 2100, she said.

Here are some questions and answers on the report from Liverman, former co-director of UA’s Institute for the Environment:

Q. What are some things Arizona can, or should, do to take a hit out of greenhouse gas emissions?

A. The first thing you might think about is Proposition 127 (a November Arizona ballot initiative that would require utilities to get half their electricity from renewable sources by 2030). For all the challenges of Prop. 127, that it will mean higher energy bills, that’s 50 percent of our electricity from renewables.

With 38 percent of Arizona’s electricity already coming from the Palo Verde Generating Station, a nuclear power plant, that takes us to 85 percent of our electricity coming from non-carbon sources. That’s in the ballpark of the scenario that might keep warming under 1.5 degrees.

(Opponents and supporters of Proposition 127 have clashed over whether the initiative would ultimately lead to closure of Palo Verde, by creating a glut of renewable energy in milder times of the year that would make Palo Verde’s electricity uneconomic).

Q. What about the higher costs, although again, supporters and opponents of the initiative have argued over how much it would raise electricity bills, if at all?

A. It will likely involve an increase in energy costs, but you could think of that as a carbon tax. If we don’t do something on that now, we may have to do something stricter later.

We may be heading in that direction anyway. In 10 years if the world has continued to warm, we may have politicians in a position to make a decision to put something like the carbon tax in place. We will have already made the transition to slightly higher costs for energy, and the ( additional) carbon tax would be lower.

Q. What about in how we design and build our homes?

A. Anything you build new should be as low emissions as possible, and well-designed for adaptation to a warmer climate. That would include shading windows, a traditional design of Territorial Arizona houses. It would mean a shaded patio around the house, so the sun doesn’t directly hit the house. It would mean thicker walls and a design to capture breezes. Many of these are characteristics of traditional homes of the desert.

Q. What about existing buildings?

A. We need to think of retrofit for existing buildings — more solar on homes and institutions. We have to accelerate that in order to meet the challenge of mitigation.

Of course we have to minimize water use, because at the moment CAP (Central Arizona Project) water is all pumped with coal fired electricity.

Some of these transitions are already happening in Arizona. Whether it’s Navajo Generating Station (the coal-fired plant powering most of CAP’s water deliveries) going out, or Prop. 127 passing, these would all be going in the direction of taking us to reducing emissions.

Q. What about transportation?

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A. We could play a role with biogeneration of fuels. Kimberly Ogden, acting vice president for research at the UA, is doing a bunch of research on biofuels, and that’s what we need for the transportation sector, to decarbonize. It involves growing certain crops that you can convert to alcohol. She’s using algae in tanks to create an airline fuel out of alcohol.

But there is a concern about bioenergy expressed in the report. It would require converting large areas of land to growing bioenergy crops which could compete with agriculture.

Q. What advantages does Arizona have over other states?

I think that Arizona has more advantages than most states, partly because of our solar potential, and partly because we’ve maintained a commitment to nuclear for better or worse, that we have Palo Verde. Partly, it’s because we are already designed to live in a hot, dry climate.

Partly, it’s because surveys have shown Arizonans are concerned about climate change. I’m not going to say it will be easy.

Q. But while ours and Phoenix’s downtowns have come a long way lately, our basic development model is still sprawl, which requires long traveling distances that require a lot of gas.

A. You could think of some ways in which new development in the periphery of city could have a lower environmental impact, built with solar, with water efficiency. People with electric cars, and people who telecommute from home. In general, based on certain conditions, infill is preferable. It tends to be smaller houses with a smaller footprint.

But you have to do a whole life cycle analysis: what the people are eating and what they are driving. If they are downtown in a solar apartment building and biking to work and use water efficiently, those individuals will be having less of an impact on greenhouse gas emissions.

But you can have a pretty brick building downtown that is unsustainable ... There are people who live downtown and drive to suburbs to work.

Q. But our state’s politics — Gov. Doug Ducey now believes that humans play a role in climate change, which he didn’t before, but he and the Legislature don’t believe in new regulations to reduce greenhouse gas emissions.

A. Consumers can influence that. There are marketplace mitigation processes. You can have carbon tax, or carbon (emissions) trading. You can include damages from climate change in prices of energy if that’s what you mean by market based solutions. Or, the state can invest in R&D, so we can develop solutions that will help everybody.

Contact reporter Tony Davis at tdavis@tucson.com or 806-7746. On Twitter@tonydavis987