Economics: Current Climate Models Are Grossly Misleading

Nature - Nicholas Stern

Nicholas Stern calls on scientists, engineers and economists to help policymakers by better modelling the immense risks to future generations, and the potential for action.

Sathkira District, Bangladesh, still flooded a year after 2009's Cyclone Aila. Jonas Bendiksen/Magnum

The twin defining challenges of our century are overcoming poverty and managing climate change. If we can tackle these issues together, we will create a secure and prosperous world for generations to come. If we don't, the future is at grave risk.
Researchers across a range of disciplines must work together to help decision-makers in the public, private and non-profit sectors to rise to these challenges. Economists, in particular, need more help from scientists and engineers to devise models that provide better guidance about what will happen if we succeed or if we fail.
As the 2015 Paris agreement on climate change made clear, we must achieve a net-zero carbon economy this century. Doing so will require policies that drive innovation, investment and entrepreneurship. The political will to make the necessary decisions depends partly on improving the analysis and estimates of the economics of climate change. Then the consequences of unmanaged global warming can be weighed much more transparently against the investments and innovations necessary to mitigate it.
Current economic models tend to underestimate seriously both the potential impacts of dangerous climate change and the wider benefits of a transition to low-carbon growth. There is an urgent need for a new generation of models that give a more accurate picture.

Dark impacts
The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), published in 2013 and 2014, provided a comprehensive overview of the literature on the costs of action and inaction. But the assessment understated the limitations of the research done so far. Essentially, it reported on a body of literature that had systematically and grossly underestimated the risks of unmanaged climate change. Furthermore, that literature had failed to capture the learning processes and economies of scale involved in radical structural and technical change, and the benefits of reducing fossil-fuel pollution, protecting biodiversity and forests, and so on.
The IPCC pointed out¹ that estimates of losses resulting from a 2 °C increase in mean global temperature above pre-industrial levels ranged from 0.2% to 2% of global gross domestic product. It admitted that the global economic impacts are "difficult to estimate" and that attempts depend on a large number of "disputable" assumptions. Moreover, many estimates do not account for factors such as catastrophic changes and tipping points.
It is these hard-to-predict impacts that are the most troubling potential consequences of inaction. The next IPCC report needs to be based on a much more robust body of economics literature, which we must create now. It could make a crucial difference.
Many estimates of economic losses are based on the outputs of integrated assessment models (IAMs). These models attempt to combine the key elements of biophysical and economic systems. This is a worthy endeavour. Sadly, most IAMs struggle to incorporate the scale of the scientific risks, such as the thawing of permafrost, release of methane, and other potential tipping points. Furthermore, many of the largest potential impacts are omitted, such as widespread conflict as a result of large-scale human migration to escape the worst-affected areas.
For instance, there is evidence that temperature increases of 1.5 °C and 2 °C would lead to differing extents of sea-level rise and extreme weather events², with obvious implications for small island states and coastal communities. These differences are simply not represented in the flawed estimates of economic losses.
IAMs are also used to calculate the social cost of carbon (SCC). They attempt to model the incremental change in, or damage to, global economic output resulting from 1 tonne of anthropogenic carbon dioxide emissions or equivalent. These SCC estimates are used by policymakers in cost–benefit analyses of climate-change-mitigation policies.
Because the IAMs omit so many of the big risks, SCC estimates are often way too low. As a first step, the consequences being assessed should include the damages to human well-being and loss of life beyond simply reduced economic output. And the very large uncertainty, usually involving downward bias, in SCC estimates should always be made explicit.
As the IPCC acknowledged², published SCC estimates "lie between a few dollars and several hundreds of dollars". These values often depend crucially on the 'discounting' used to translate future costs to current dollars. The high discount rates that predominate essentially assume that benefits to people in the future are much less important than benefits today.
These discount rates are central to any discussion of our hand in the fate of future generations. Most current models of climate-change impacts make two flawed assumptions: that people will be much wealthier in the future and that lives in the future are less important than lives now.
The former assumption ignores the great risks of severe damage and disruption to livelihoods from climate change. The latter assumption is 'discrimination by date of birth'. It is a value judgement that is rarely scrutinized, difficult to defend and in conflict with most moral codes.

Costing transition
The other role of IAMs — to estimate the costs of climate-change mitigation — also suffers from major shortcomings.
The IPCC's mitigation assessment³ concluded from its review of IAM outputs that the reduction in emissions needed to provide a 66% chance of achieving the 2°C goal would cut overall global consumption by between 2.9% and 11.4% in 2100. This was measured relative to a 'business as usual' scenario. Clearly, growth itself can be derailed by climate change from business-as-usual emissions.
So the business-as-usual baseline, against which costs of action are measured, conveys a profoundly misleading message to policymakers that there is an alternative option in which fossil fuels are consumed in ever greater quantities without any negative consequences to growth itself.
Crucially, IAMs generally omit the potentially huge costs of air pollution from fossil fuels — which are saved if alternative fuels are used⁴. IAMs struggle to describe developments in alternative energy. They fail, in general, to capture the feedback loops in the innovation process that interact across the economy, prompting institutional and behavioural change, possible discoveries and economies of scale. There is empirical evidence, for example, that the geographical location of researchers and inventors can affect whether a firm chooses to do clean or dirty innovation.

"Discount rates are central to any discussion of our hand in the fate of future generations."

The initial investment required to catalyse the transition to a low-carbon pathway might lead to great economic benefits in the long run. These could go well beyond avoided climate risks⁵. The knowledge spillover from low-carbon innovation into the wider economy — for instance, a battery developed for electric vehicles being used in wheelchairs — seems to be greater overall than that from high-carbon-energy technologies⁶.
As engineers learn how to install, connect and repair technology cheaply, unit costs fall faster for many new technologies than for existing ones. This has already allowed solar-photovoltaic and onshore-wind technologies to become competitive with natural gas and coal in several locations, even without emissions taxation.
Also influential will be the emergence of new networks, such as the integration of electric-vehicle-energy storage into smart grids, as well as rapid technical progress. And these steps can be accelerated if, for example, consumers change behaviour and demand support for resource efficiency, recycling and pedestrianization. It is clear that much will depend on urban management and design; as cities grow rapidly, damaging infrastructure can become 'locked in'.

What's needed?
There is much that can be done to make the assumptions in standard IAMs more realistic with respect to the scale and nature of damages^{7, 4}. But to give policymakers the reliable information that they need when implementing the Paris agreement, incremental improvements^{7, 8} to the present generation of IAMs may not be enough.
A comprehensive review of the problems of using IAMs in climate economics⁵ called for the research community to develop a "third wave" of models. The authors identify various types of model that might offer advances. Two are: dynamic stochastic computable general equilibrium (DSGE) models, and agent-based models (ABMs).
Like current IAMs, DSGE models can explicitly account for uncertainty about the future through the introduction of shocks, for instance, to economic output, consumption or climate damages⁹. ABMs, by contrast, seek to provide more-realistic representations of socio-economics by simulating the economy through the interactions of a large number of different agents, on the basis of specific rules. ABMs are widely used in finance, but have yet to be seriously applied to climate change. These are promising developments.
Now, a concerted effort is required by the research community to explore as many potential avenues as possible to better estimate the costs of action and inaction on climate change. The IPCC should distil what policymakers need to inform their decision-making. Learned societies and national academies must bring together researchers from a wide range of relevant disciplines to focus attention on improving economic modelling quickly.
Bangladeshi farmers and Cairo city-dwellers are at severe risk of flooding and storms; southern Europe and parts of Africa and the Americas are threatened by desertification. Perhaps hundreds of millions of people may need to migrate as a result, posing an immense risk of conflict.
There is huge potential in future technologies that can drive change. These are omitted or badly underestimated in our current climate modelling — deeply damaging our guidance for policymaking. The well-being and prosperity of future generations are worth more.

References

1. IPCC. Climate Change 2014: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge Univ. Press, (2014).
2. Schaeffer, M. et al. Nature Clim. Change 2, 867–870 (2012).
3. IPCC. Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge Univ. Press, 2014).
4. Stern, N. Why are We Waiting?: The Logic, Urgency, and Promise of Tackling Climate Change (MIT Press, 2015).
5. Aghion, P. et al. Path Dependence, Innovation and the Economics of Climate Change (Grantham Research Inst., 2014).
6. Dechezleprêtre, A., Martin, R. & Mohnen, M. Knowledge Spillovers from Clean and Dirty Technologies: A Patent Citation Analysis (Grantham Research Inst., 2013).
7. Dietz, S. & Stern, N. Econ. J. 583, 574–620 (2015).
8. Gillingham, K. et al. National Bureau of Economic Research Working Paper No. 21637 (2015).
9. Golosov, M. et al. Econometrica 82, 41–88 (2014).

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CSIRO Executives To Face Fresh Scrutiny Over Planned Cuts To Climate Science

Fairfax - Peter Hannam

CSIRO chief executive Larry Marshall is expected to face another grilling over the plans to cut 350 scientists. Photo: Daniel Munoz

CSIRO executives are likely to face another grilling over their plans to lop 350 jobs, including many climate scientists, with a Senate committee planning a fresh inquiry next month.
Greens Senator Peter Whish-Wilson will use the scrutiny of budget measures committee that he heads to dig deeper into the strategy behind the cuts – announced on February 4 – at a special hearing "as soon as possible" in Hobart.
"This will give the scientific community and other stakeholders a chance to make submissions," the Tasmanian senator told Fairfax Media.
"Evidence to date suggests the decision was made with little insight or understanding of its consequences."
The Senate also turned the heat up further on CSIRO management on Wednesday by passing an order for the production of documents proposed by deputy Greens leader Larissa Waters.
CSIRO executives will have to provide a series of documents by no later than March 3, including internal communications that saw a proposed cut of about 35 staff to two key climate units doing monitoring and model work swell to almost triple that figure within about a month over Christmas.
The race may be tight, though, with staff in Ocean and Atmosphere and the Land and Water divisions told in separate meetings this week that staff to be made redundant will be informed by March 14, a senior scientist told Fairfax Media.
Fairfax Media sought comment on the Senate moves from CSIRO.
At Senate estimates earlier this month, chief executive Larry Marshall said the two units within the Oceans and Atmosphere division would eventually halve the current levels of 140.
The cuts were necessary to divert more resources to climate change mitigation and adaptation, Dr Marshall said.
Other cuts in the 350 tally, though, are likely to fall heavily on climate change adaptation programs within the Land and Water division.
An all-staff meeting of the division on Tuesday also heard that the promise that the reductions would be made up over two years – as Dr Marshall has stated – would hinge on whether revenue in the division increased, Fairfax Media has learned from a senior researcher who listened in to the discussion.

Link

• 'A thing of beauty': CSIRO skills made redundant

Global Ocean Monitoring Program Struggling To Stay Afloat, Warn Scientists

The Guardian - Graham Readfearn

The Argo array of ocean floats supported by 31 countries has 'revolutionised' our understanding of the oceans but its future is uncertain

An Argo float is deployed into the ocean Photograph: CSIRO

Right now, roughly a kilometre below the surface of an ocean near you, a yellow cylinder about the size of a golf bag is taking measurements of the temperature and saltiness of the water.
Every couple of days, the float will drop deeper – down to 2km – and then rise to the surface to transmit its data, before disappearing back into the depths to do the whole thing again.
These floats do this for as long as eight years, until the poor little things die of exhaustion (well, their batteries run out).
There are about 3,800 of these floats scattered across the globe as part of a program called Argo, supported by more than 30 countries.
It's likely you've never heard of Argo and much less likely you've ever seen one of the floats.
But for the last decade, climate scientists and oceanographers have been using the data from these Argo floats to plug a gaping ocean-sized hole in our understanding of global warming.
Scientific papers that use the data from these floats are now appearing in science journals at the rate of about one per day.
But now, scientists are sounding an alarm for the future of this ocean monitoring system. In a commentary in the journal Nature Climate Change, scientists say cracks are starting to appear in the network, largely because of uncertainties over funding.
The commentary predicts it could be only two years before the number of floats drops below a critical threshold of 3,200, which would "considerably undermine the ability of the observing system to monitor and measure the global ocean".

Chart showing forecasted deployments of Argo ocean monitoring floats Photograph: Paul Durack

Australian Dr Paul Durack, of the US government-funded Program for Climate Model Diagnosis and Intercomparison at the Lawrence Livermore National Laboratory, is one of the scientists sounding the alarm. He told me:

Argo is an amazing entity – there are at least 30 nations involved – and it's giving us observations that we have never had before. From about 2005, Argo gave us comprehensive ocean data – if you don't have data you can't say anything. Basically, it has completely changed the game.

Knowing what's happening in the globe's oceans is critical. About 90% of the extra heat from human-caused global warming has ended up there.

When you get below a couple of hundred metres you see the inexorable growth of global warming happening in the oceans Dr Susan Wijffels

Some 31 countries have contributed to the Argo program, with floats costing about US$25,000 each. The United States funds about half, with about 2,142 of the floats currently in circulation.
France is the second-biggest supporter, with 356 floats, followed by Australia with 346. Two-thirds of the global ocean is in the southern hemisphere.
CSIRO's Dr Susan Wijffels is the co-chair of the global Argo program and also the lead scientist for Australia's contribution to Argo.
In the Nature Climate Change commentary, Wijffels says any drop in the number of deployments of floats could spell trouble. She told me:

Argo is fundamental because this all comes back to the heat problem. The key thing that matters for the Earth is how much extra heat is retained in the system.
While we have seen this huge debate over the last 15 years about this so-called 'hiatus', really what Argo shows us is that surface variability [in temperature] is just a re-organisation of heat.
When you get below a couple of hundred metres you see the inexorable growth of global warming happening in the oceans. That's driving a good chunk of the sea level rise. It is telling us what the radiation imbalance is at the top of the atmosphere.
Once that heat and that carbon is down there in the deep ocean it's there for decades – if not longer – and it's locking in that warming. We see that warming in Argo right down to the depths of our measurement – right down to two kilometres and its probably extending further.

Oceanographer Prof Dean Roemmich, of the Scripps Institution of Oceanography at the University of California, San Diego, is also a co-chair of the global Argo program. He told me why there's a fear the comprehensive coverage that Argo gives the world's oceans could be at risk.

In most nations Argo is supported by research funds – rather than as operational oceanography – with no mechanism for inflation or for long-term funding. So far Argo has been successful in increasing the lifetime of floats so that less deployments are needed to maintain the array and bringing in new national programs to sustain the level of total deployments.
Durack points out these advances are difficult to sustain and without them the array would decline. This is an important caution, and along with it we need to continue making the case for Argo's great value in order to increase support from Argo national programs.

Roemmich says Australian scientists are "world leaders in basic research using Argo data, particularly in the Southern Ocean" and that the country also provides critical operational support.
Tim Moltmann is the director of the Integrated Marine Observing System (IMOS), a program funded by the Department of Education and Training and which has provided about half the funding for Australia's Argo program over the past decade.

It has been revolutionary. What we knew about the subsurface ocean before Argo was pretty much limited to what we could get from ships – dropping instruments into the water and getting measurements. You can imagine that's pretty sparse.
What's critically important from an Australian perspective is that from a historical point of view, measurements of the oceans have been dominated by the northern hemisphere.
Argo has been critically important for Australia and the southern hemisphere because it has enabled us to bootstrap our subsurface observing capability in a remarkable way.
That's how we know that ocean heat content is changing. That's how we know that so-called 'pause' [in global warming] isn't really a pause if you look at the whole system, because the heat has been building up in the ocean.

IMOS has funded about half of Australia's Argo effort so far, says Moltmann.
Over the past decade, about 20% of the funding for Australia's Argo program has come from the CSIRO, which also employs about four full-time staff who work to understand and interpret the data and maintain the floats.
Paul Durack is also the scientist who helped to coordinate an open letter signed by almost 3,000 scientists from 60 countries calling on CSIRO to reconsider planned cuts to its climate change research.
He is worried those cuts could make matters worse for Argo. In the commentary, written before the cuts were announced, Durack writes:

Future forecasts are inherently difficult to generate, due to the short-term nature of national budgets, along with unanticipated technology and deployment problems or new technology breakthroughs. These are further confounded by a critical dependence on each and every nation that contributes to the array – and a loss of just one of these key contributors will have a profound impact.

CSIRO chairman David Thodey wrote last week that the agency was "committed" to "contribute to the international Argo floats program".
But when I asked for details of the commitment and whether the cuts would impact on Argo, a CSIRO spokesperson would only say the agency was "currently working through the impacts of the strategic realignment" with staff and research partners.

Links

• World's oceans warming at increasingly faster rate, new study finds
• Floating robots primed for release to capture elusive ocean data
• Fossil fuel emissions behind Australia's record-breaking spring heat, suggests study
• Climate change in charts: from record global temperatures to science denial

Longest Global Coral Bleaching On Record Isn’t Over Yet

Climate Central - Brian Kahn

Coral reefs have had a rough run over the past two years. Climate change has ratcheted up ocean temperatures and El Niño helped kick them into overdrive in parts of the world. All that heat kicked off what has been a major coral die-off around the globe.

Coral bleaching alert levels over the past 30 days.

Credit: Coral Reef Watch

While El Niño has passed its peak, scientists have warned that the global coral die-off, known as coral bleaching, is still far from over. What began in 2014 is projected to continue through this year and even into early 2017.
This is the third global bleaching event on record. The others were in 1998 and 2010, both El Niño years. El Niño, which is marked by warmer than normal waters in the tropical Pacific, has certainly played a role. The steady background creep of ocean warming due to climate change, however, is also an important factor. More than 90 percent of the accumulated heat due to climate change is ending up in the oceans and its effects are being acutely felt.
"We are currently experiencing the longest global coral bleaching event ever observed," Mark Eakin, the Coral Reef Watch coordinator, said in a statement.
The prolonged exposure to high water temperatures has left many reefs in critical shape. The warm water causes corals to expel the algae they rely on to grow, leaving ghostly white skeletons in the place of thriving coral communities.

Coral bleaching forecast for March-June.

Credit: Coral Reef Watch

The Pacific Ocean has been the epicenter of the global bleaching event and Christmas Island has been the tiny bullseye of that epicenter. The 150 square mile island sits right in the middle of the El Niño-warmed waters.
Coral there have been subjected to some of the most stressful conditions anywhere in the world. Specifically, El Niño sent water temperatures as high as 88°F, or about 6°F above normal, in the region. That extended period of stress had already killed off a wide array of corals when Kim Cobb, a coral expert at Georgia Tech, visited the reef in November during peak El Niño heat.
And though waters are cooling as El Niño ebbs, Cobb is expecting to see even more devastation when she returns to Christmas Island next month. She's using crowdfunding for the trip because of the rapid response nature of the work and the wealth of information she and other scientists can learn from.

Airport Reef in American Samoa at the height of a bleaching event in February 2015.

Credit: XL Catlin Seaview Survey

"I call it the data collection opportunity of an academic career," she said. "How this reef evolved through this mega El Niño (represents) this incredible opportunity because we know we may face more extremes in the future."
The data Cobb plans to collect will provide valuable insight into which corals survive this extreme heat event. With climate change expected to keep warming oceans, those types of insights could be key to conservation efforts, not just at Christmas Island but around the world.
And while Christmas Island should experience a reprieve with oceans returning to normal temperatures around the region later this year, other areas will continue to feel the heat. The odds are increasing for a La Niña event later this year. While that means cooler-than-normal waters for the eastern and central tropical Pacific, it ramps up temperatures in the western edge of the basin around Indonesia and the Papua New Guinea.
That area is known as the Coral Triangle, an ecologically crucial spot for coral, fish, turtles and other sea creatures. It's already under threat from the current global coral bleaching event and could face even higher risks if La Niña materializes.

Links

• These Coral Reefs Are a 'Crystal Ball' For Future Change
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• Paris Pact Promotes But Complicates Carbon Trading
• Study Reveals Stunning Acceleration of Sea Level Rise
• The Human Fingerprints on Coastal Floods

Tassie Fires Linked To Human-Induced Climate Change, Study Finds

ABC Science - Anna Salleh

Unprecedented bushfires burned out about 20,000 hectares of Tasmania's World Heritage Area last month. (Supplied: Dan Broun)

Bushfires in Tasmania are happening more frequently now than in the past 1,000 years, and human impacts on climate are likely to blame, researchers say.

Key points: Bushfires in Tasmania are more frequent now than in the past 1,000 years This is linked to southward migration of westerly winds This southward movement has been linked ozone depletion

Scientists said the increase in bushfires on the island was due to the shift of westerly winds towards Antarctica, a trend that has previously been linked to depletion of the ozone layer.
"My conviction is that the current trend is evidence of anthropogenic forces," said Dr Michael-Shawn Fletcher of the University of Melbourne, who studies long-term interactions between humans, climate and vegetation.
A belt of westerly winds north of Antarctica brings rain to southern parts of Australia including Tasmania. The movement of these winds north and south is known as the Southern Annular Mode (SAM).
During a negative SAM, westerlies move north, but during a positive SAM the winds move south and drier conditions prevail on land.
Previous research has linked a shift towards a positive SAM and the southward shift of westerlies, with depletion of the ozone layer, which affects the upper atmosphere.

Positive SAM linked to increased fire frequency
In the first ever study of its kind, Dr Fletcher and PhD student Michaela Mariani found the southerly shift in westerlies was associated with an increase in fire activity in south west Tasmania.
Their study included an analysis of charcoal deposits from fires over the past 1,000 years in an area of western Tasmania that includes areas where fires are currently burning.

Large-scale fire events in Tasmania in the past have been very rare and we're beginning to see them more frequently ... There's evidence we're seeing anthropogenic climate change. Professor David Bowman, fire ecologist, University of Tasmania

The researchers compared the amount of charcoal at different time periods to changes in SAM and found there was more charcoal at times when the westerlies had shifted southward.
The rise and fall in the amount of charcoal closely matched the SAM index, with a steady rise in both charcoal and the SAM index since around 1500, and a particularly steep rise in recent times.
"Correlation isn't causation," said Dr Fletcher. "But it's a well-described phenomenon that ozone depletion has caused a positive trend in SAM and we've got clear evidence that the SAM index in the 21st century has exceeded anything that's occurred in the last 1,000 years."
The researchers also found a close match between actual SAM and fire records on a shorter time scale, over the past 30 years.
"If you have a dry autumn, winter, spring you've got more fires in summer," said Dr Fletcher.
The research has been accepted for publication in Geophysical Research Letters.

Current Tassie fires in study area
Dr Fletcher said while the impact of El Nino-Southern Oscillation (ENSO) on fire frequency has recently been recognised, relatively little attention has been paid to the impact of SAM.
"We've ignored the fact that in Tasmania, at least, fires are also modulated by this other system," he said.
He said the current fires are likely to be a result of a combined effect of ENSO and SAM.
"What we have here in this current year is the fifth strongest El Nino event on record and the second positive SAM event on record," said Dr Fletcher. "It's a double whammy."

SAM could act as an 'early warning'
A related report appearing this week in the journal Environmental Research Letters argues that it is hard to predict fire activity in Australia because of its highly variable climate.
However senior author Professor David Bowman, a fire ecologist from the University of Tasmania, welcomed Dr Fletcher's research for showing the role SAM can have in providing "early warning" of bad fire seasons.
"You can't predict precisely, but you can use climates modes like SAM to help you forecast bad fire seasons," said Professor Bowman. "It's just a guide, but it's important."
Professor Bowman said claims that humans are increasing fire frequency were supported by different lines of evidence over long time periods over time.
"Large-scale fire events in Tasmania in the past have been very rare and we're beginning to see them more frequently," he said. "There's evidence we're seeing anthropogenic climate change."

Links

• Tasmanian bushfires: Senate calls for independent inquiry into World Heritage Area fires
• Number of bushfires per week in Australia 'increased by 40 per cent' between 2008 and 2013
• Stronger winds chilling Australia's rainfall

Solar Is So Hot Right Now. Check Out The Latest Numbers

Grist - Melissa Cronin

Flickr/Intel Free Press

The solar energy industry is absolutely crushing it right now. For the first time ever, more solar power capacity was installed in the U.S. last year than natural-gas capacity.
The U.S. solar market grew by 17 percent in 2015, according to new figures released by the Solar Energy Industries Association (SEIA), and it's expected to grow even more. The growth is a record-breaker, amounting to 7,286 megawatts of solar photovotaics installed.

SEIA also released a state-by-state breakdown of solar installations in 2015. California remains, unsurprisingly, in first place, followed by North Carolina and Nevada. But other states, like Utah and Georgia, saw huge strides last year and are quickly climbing the list. And individual homeowners are starting to hop aboard the solar train by the droves: the residential solar market grew 66 percent, and now represents its largest share of the overall market since 2009.
The fact that solar is now outpacing natural gas is good news for climate hawks and for anyone who dislikes massive, polluting leaks that spew rotten-smelling fumes into populated areas. The barriers to entry for solar are quickly crumbling, with the price of installing new panels plummeting in recent years. Giant companies like Apple are boarding the solar bandwagon, signing enormous contracts to snatch up incredible amounts of solar power for their facilities.
The boom in solar is largely due to the federal solar Investment Tax Credit, a measure meant to incentivize both residential and commercial solar installations. Late in 2015, Congress voted to extend a 30 percent tax credit through 2019—a move that came as a godsend for the solar industry. At least until then, it looks like solar is poised to keep on soaring, as more people realize that clean air and the general stability of the planet are things that we all desperately need.

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How to Keep Companies Honest About Fighting Climate Change

Time - Justin Worland

Business represents the next frontier in efforts to address climate change

Steam rolls out of a factory's smoke stack in Dayton, Ohio. J.D. Pooley—Getty Images

Going green is the latest corporate trend—but it can be tough to separate the companies that are actually making major environmental commitments from those that are just giving lip service to the cause.
Now that Walmart, Google, Goldman Sachs and other international corporations have pledged to cut their carbon footprint—commitments that would have been almost unimaginable a decade ago—climate leaders are turning their attention to the next challenge: ensuring that companies follow through on their promises. That's the aim of a new effort spearheaded by the U.N.'s recently appointed climate champion, French climate change ambassador Laurence Tubiana. She hopes to build a system that measures corporate efforts to address climate change, with non-governmental organizations playing a role as fact checkers.
"All sorts of institutions have registered their various commitments," says Mark Kenber, CEO of The Climate Group, an advocacy group that works with dozens of corporations. "Some of those were real commitments and some of those were high level 'we'll think about doing something.' How do we find a common set of methodologies and monitoring, verification and reporting systems so things can be compared?"
Tubiana, a key figure at the Paris climate conference in December, is still determining the form of the future transparency system, but here's how climate policy experts say you should evaluate a corporate climate commitment:

1. Support from top executives
Strong climate commitments should be approved at a company's highest levels with consent of the board of directors. Such high-level commitment helps ensure that the company leadership sees addressing global warming as a key part of the corporate strategy and will be less likely to abandon commitments on a whim.

2. Concrete goals
Companies should also make their goals concrete and offer a plausible path to meet them. That means an assessment of where across the supply chain—including in transportation and products purchased from outside vendors—carbon emissions come from and a plan to address those specific issues. And, while reasonable goals may only extend a decade or so into the future, companies should have a plan to reassess and strengthen them going forward.
"Good environmental management is good business management," says Tom Murray, who runs the corporate partnerships program at the Environmental Defense Fund. "A big part of that is setting big goals and delivering on that."

3. Transparent reporting
Perhaps most importantly, climate policy experts say companies should report on their progress transparently and offer a way for external experts to verify the information. In some ways, outside verification is easy. Top-tier accounting firms like Deloitte and KPMG have developed methods to audit companies' sustainability efforts. But the audits come with a hefty price tag, and companies are often unwilling to add to their bottom line without a strong business incentive.
Once a transparency system has been implemented, and companies begin to comply, policy experts will gain a sense of how much progress has been achieved by the private sector toward cutting greenhouse gas emissions. One estimate from the Climate Group suggests that a commitment from the world's 1,000 biggest companies to go 100% renewable would result in a 15% global reduction in carbon emissions. Around 50 companies have signed up already, including a slew of household names like Johnson and Johnson, Starbucks and Microsoft.
Just a decade ago, opposition to new regulation from corporate leaders made it difficult to address climate change. Some companies allegedly went as far as obscuring evidence supporting the existence of climate change.
Today, corporations are more likely to take on carbon emissions as a serious issue. They're partly motivated by the strong argument that climate change could wreak havoc on the global economy, destroying the markets that many companies need to sell their products and services. A 2015 report from financial services firm Citigroup found that keeping temperature rise to 2.7ºF (1.5ºC) instead of 8.1ºF (4.5ºC), the do-nothing scenario, in the coming decades would minimize global GDP loss by $50 trillion. Companies have also realized there's a lot to be gained from switching to low-carbon technologies, including a long-term reduction in energy costs.
"Right now we're seeing companies step up and be supportive of climate policy in a way that I think is new and goes beyond what they've done before," says Murray. "If you think about leadership being a curve, people are working their way up it."

Links

• Air Pollution Kills More Than 5 Million People Around the World Every Year
• Oceans Are Rising at Fastest Rate in 3,000 Years, Study Says