The Bulletin’s Science and Security Board announces its 2013 decision to keep in place the minute hand of the Doomsday Clock: It will remain at five minutes to midnight. In this open letter to US President Barack Obama, the Board presents its views on the key issues that affected its decision and provides the president with recommendations to consider in 2013 and throughout his second term.

The Bulletin of the Atomic Scientists’ Doomsday Clock “conveys how close humanity is to catastrophic destruction–the figurative midnight–and monitors the means humankind could use to obliterate itself.” These means include “nuclear weapons, but they also encompass climate-changing technologies and new developments in the life sciences that could inflict irrevocable harm.”

This year, the Bulletin’s Science and Security Board, “in consultation with its Board of Sponsors, which includes 18 Nobel Laureates,” left the clock at 5 minutes to midnight. The Board also took the unusual step of releasing a powerful open letter to President Obama. I’ll excerpt the climate change parts of that letter below:

Dear President Obama,

2012 was a year in which the problems of the world pressed forward, but too many of its citizens stood back. In the US elections the focus was “the economy, stupid,” with barely a word about the severe long-term trends that threaten the population’s well-being to a far greater extent: climate change, the continuing menace of nuclear oblivion, and the vulnerabilities of the world’s energy sources. 2012 was the hottest year on record in the contiguous United States, marked by devastating drought and brutal storms. These extreme events are exactly what climate models predict for an atmosphere overburdened with greenhouse gases….

The stasis of 2012 convinces us, the Science and Security Board, to keep the hands of the Doomsday Clock in place.

Mr. President, we see 2013 as a year for vision and engagement. We know that decisive action can make the world safer. Humanity awaits the US leadership that can secure a future free of nuclear weapons. US action can induce the world’s nations to negotiate international agreements to avert the worst calamities of climate change. We turn to you, Mr. President, to lead us toward a safer world and to help us turn back the hands of the Doomsday Clock.

It remains five minutes to midnight….

Climate change. Human activities are now the dominant cause of global climate change. Emissions of heat-trapping gases continued to climb in 2012, with atmospheric levels of carbon dioxide — the most important greenhouse gas affected by human activities — reaching levels higher than at any time in the past 800,000 years. 2012 was the hottest year on record for the contiguous United States. Arctic sea ice continued to rapidly diminish in extent, reaching a record low this past year that fell under the previous low by an area the size of Texas. Glaciers are retreating, and the massive Greenland and Antarctic ice sheets are losing mass. Extreme weather events, such as last year’s Superstorm Sandy and Typhoon Bopha, now strike in an environment altered by climate change, with higher sea surface temperatures and more water vapor in the atmosphere to fuel and sustain their destructive power.

But 2012 also provided further evidence of the viability of renewable sources of energy and more efficient ways of powering the global economy, pointing toward an alternative to the high-carbon development model. Wind and solar power, for example, expanded at rates greatly exceeding what energy agencies forecasted earlier this decade. Owing to supportive policies, power generation from these sources expanded nearly fourfold over the past five years in the United States, and even more so in other countries, including Germany and China, where there they enjoyed stronger support. The new US automobile fuel economy standard was another welcome development, promising nearly a doubling of vehicle efficiency by 2025.

This trend, while encouraging, is by no means evidence that the climate challenge has been met. In fact, the growth in low-carbon energy sources is dwarfed by the continued expansion of fossil fuels like coal — as was exemplified last year by the explosive development of unconventional fossil resources, such as tar sands, oil shale, and shale gas. With life-cycle greenhouse gas emissions that are even worse than their conventional counterparts, these unconventional fossil resources threaten to crowd out investment in renewables and to entrench a long-term dependency on carbon-intensive energy supplies.

Avoiding this scenario will require your administration to considerably speed the process of reforming the patchwork of federal subsidies, taxes, and other incentives and disincentives that distort energy markets. We look forward to substantial progress toward rational energy markets in 2013, including the pricing of greenhouse gas emissions throughout the economy.

2012 saw the arrival of an apparently abundant domestic natural gas resource, which could be an important contributor to a more environmentally sound energy future. We call on your administration to see that commercialization of this resource is pursued in ways that mitigate its environmental impacts, including its climate change impacts. Specifically, we urge you to create strong regulations for gas developers to minimize methane leakage and safeguard water resources, and for power-plant developers to incorporate carbon dioxide capture and storage.

Mr. President, you have taken some steps to help nudge the country along a more rational energy path. You kept alive the incentives for wind and other renewable power, and you strengthened vehicle fuel-efficiency standards. These are important steps, but without a concerted effort to launch a comprehensive and ambitious response to the climate challenge in 2013, we face diminishing prospects for averting the worst and most costly effects of a disrupted climate.

Since your re-election, you have noted with concern that the Earth is warming and the Arctic ice cap is melting even faster than scientists had predicted, while extraordinary weather events — from storms to droughts — are taking their toll in the United States and around the world. You also stressed that we have an obligation to future generations to do something about climate change, and you promised that this would be a priority of your administration.

In September 2013, the Intergovernmental Panel on Climate Change (IPCC) will publish its fifth assessment of climate science, which will authoritatively document the changing climate. We call on you to commit your administration to firmly accept the panel’s scientific findings, urgently integrate these findings into national policy, and confidently face those who irresponsibly argue that climate change science is not relevant….

Next steps. Mr. President, with your second inauguration one week away, we have as much hope for your presidency as we did in 2010, when we moved back the hands of the Doomsday Clock after your first year in office. You have an extraordinary capacity to articulate the global desire for peace and security, and you have the tools to deliver tangible progress. Your Prague speech on nuclear disarmament and your efforts at Copenhagen to coordinate world leaders to slow the onset of climate change are high water marks in their respective basins of activity. We call on you to reinvigorate these initiatives. Specifically:

•Prioritize climate change at a level that recognizes the gravity of the climate threat. You have the ability to educate and inspire the United States to launch an ambitious response, confront entrenched interests that have forestalled action, and, if Congressional dysfunction prevents legislative action, you are able to use your executive powers to achieve progress on a rational energy and climate strategy for the nation.

•Partner with other world leaders to forge the comprehensive global response that the climate threat demands, based on equity and cooperation across countries. A global solution will only be within reach if the United States commits to doing its fair share by investing at home and globally to curb greenhouse gas emissions, while building resilience in the face of the climate disruption that is now unavoidable.

•Reform the patchwork of federal subsidies, taxes, and other incentives and disincentives so as to encourage large reductions in US greenhouse gas emissions.