Tag Archives: greenhouse gases

NASA and NOAA Agree: 2014 Was Hottest Year On Record

Though it might be hard to believe right now since the Northern Hemisphere is currently experiencing the coldest part of winter, our average global temperatures are increasing at a worrying rate. NASA and NOAA have analyzed the data independently of one another and yet have arrived at the same conclusion: 2014 is the warmest year on record since 1880. This is the 38th consecutive year with above average surface temperatures. The dataset has been released by NASA’s Goddard Institute for Space Studies (GISS).

“NASA is at the forefront of the scientific investigation of the dynamics of the Earth’s climate on a global scale,” NASA’s John Grunsfeld said in a press release. “The observed long-term warming trend and the ranking of 2014 as the warmest year on record reinforces the importance for NASA to study Earth as a complete system, and particularly to understand the role and impacts of human activity.”

Surface temperatures in 2014 averaged 0.8° C (1.4° F) warmer than 1880. This doesn’t mean that 1880 was a particularly hot year; it’s just where the instrumental record begins. It might not seem like a significant increase, but it can have an incredible impact on the environment. This increase has been largely attributed to carbon dioxide released into the atmosphere due to human activity.

Those living in the Midwest or East Coast of the United States will remember last year’s Polar Vortex, which brought extreme winter weather to hundreds of millions of people. However, other parts of the country experienced record-setting temperatures during the summer, offsetting the cold experienced during the winter.

Overall, the planet has been growing increasingly warmer for several decades. Variations in weather patterns have created slight cooling periods, but looking at the larger picture shows that temperatures are definitely looking up, and not in a good way. In fact, nine out of the 10 warmest years since the record began have happened after 2000. The exception is 1998, due to the intense effects of El Niño. 2014 was not affected by El Niño.

Image credit: NASA, Hansen et al. (2010)

“This is the latest in a series of warm years, in a series of warm decades. While the ranking of individual years can be affected by chaotic weather patterns, the long-term trends are attributable to drivers of climate change that right now are dominated by human emissions of greenhouse gases,” noted Gavin Schmidt, GISS Director.

Though NASA and NOAA have agreed that 2014 was the warmest year since the Industrial Revolution, they used different methods for data collection. Researchers at GISS combined data from 6,300 weather stations to get land temperatures, while ocean temps were retrieved via ships, buoys, and from the Antarctic. NOAA’s conclusion also came from data collected by ships and buoys, though it made use of satellite and radar data as well.



Read more: http://www.iflscience.com/environment/nasa-and-noaa-agree-2014-was-hottest-year-record

What Would Happen To The Climate If We Stopped Emitting Greenhouse Gases Today?

Earth’s climate is changing rapidly. We know this from billions of observations, documented in thousands of journal papers and texts and summarized every few years by the United Nations’ Intergovernmental Panel on Climate Change. The primary cause of that change is the release of carbon dioxide from burning coal, oil and natural gas.

International climate talks in Lima this week are laying the foundation for next year’s UN climate summit in Paris. While negotiations about reducing emissions grind on, how much warming are we already locked into? If we stop emitting greenhouse gases tomorrow, why would the temperature continue to rise?

Basics of carbon and climate

The carbon dioxide that accumulates in the atmosphere insulates the surface of the Earth. It’s like a warming blanket that holds in heat. This energy increases the Earth’s surface average temperature, heats the oceans and melts polar ice. As consequences, sea level rises and weather changes.

Global average temperature has increased. Anomalies are relative to the mean temperature of 1961-1990. Finnish Meteorological Institute and Finnish Ministry of the Environment, Author provided

Since 1880, after carbon dioxide emissions took off with the Industrial Revolution, the average global temperature has increased about 1.5F (0.85C). Each of the last three decades has been warmer than the preceding decade, as well as warmer than the entire previous century.

The Arctic is warming much faster than the average global temperature; ice in the Arctic Ocean is melting and the permafrost is thawing. Ice sheets in both the Arctic and Antarctic are melting. Ecosystems on both land and in the sea are changing. The observed changes are coherent and consistent with our theoretical understanding of the Earth’s energy balance and simulations from models that are used to understand past variability and to help us think about the future.

A crack in Antarctica’s Pine Island Glacier. NASA Goddard Space Flight Center, CC BY

Slam on the climate brakes

What would happen to the climate if we were to stop emitting carbon dioxide today, right now? Would we return to the climate of our elders? The simple answer is no. Once we release the carbon dioxide stored in the fossil fuels we burn, it accumulates in and moves amongst the atmosphere, the oceans, the land, and the plants and animals of the biosphere. The released carbon dioxide will remain in the atmosphere for thousands of years. Only after many millennia will it return to rocks, for example, through the formation of calcium carbonate – limestone – as marine organisms’ shells settle to the bottom of the ocean. But on time spans relevant to humans, once released the carbon dioxide is in our environment essentially forever. It does not go away, unless we, ourselves, remove it.

If we stop emitting today, it’s not the end of the story for global warming. There’s a delay in temperature increase as the climate catches up with all the carbon that’s in the atmosphere. After maybe 40 more years, the climate will stabilize at a temperature higher than what was normal for previous generations.

This decades-long lag between cause and effect is due to the long time it takes to heat the the ocean’s huge mass. The energy that is held at the Earth by the increased carbon dioxide does more than heat the air. It melts ice; it heats the ocean. Compared to air, it’s harder to raise the temperature of water – it takes time, decades. However, once the ocean temperature is elevated, it adds to the warming of the Earth’s surface.

So even if carbon emissions stopped completely right now, as the oceans catch up with the atmosphere, the Earth’s temperature would rise about another 1.1F (0.6C). Scientists refer to this as committed warming. Ice, also responding to increasing heat in the ocean, will continue to melt. There’s already convincing evidence that significant glaciers in the West Antarctic ice sheets are lost. Ice, water, and air – the extra heat held on the Earth by carbon dioxide affects them all. That which has melted will stay melted – and more will melt.

Ecosystems are altered by natural and manmade occurrences. As they recover, it will be in a different climate from that in which they evolved. The climate in which they recover will not be stable; it will be continuing to warm. There will be no new normal, only more change.

Glacial ice loss over Greenland and Antarctica from 2003 to 2010.

Best of the worst case scenarios

In any event, it’s not possible to stop emitting carbon dioxide today, right now. Despite significant advances in renewable energy sources, total demand for energy accelerates and carbon dioxide emissions increase. I teach my students that they need to plan for a world 7F (4C) warmer. A 2011 report from the International Energy Agency states that if we don’t get off our current path, then we’re looking at an Earth 11F (6C) warmer. Our current Earth is just over 1F warmer, and the observed changes are already disturbing.

There are many reasons that we need to essentially eliminate our carbon dioxide emissions. The climate is changing rapidly; if that pace is slowed, the affairs of nature and human beings can adapt more readily. The total amount of change, including sea-level rise, can be limited. The further we get away from the climate that we have known, the more unreliable the guidance from our models and the less likely we will be able to prepare. The warmer the planet gets, the more likely reservoirs of carbon dioxide and methane, another greenhouse gas that warms the planet, will be released from storage in the frozen Arctic permafrost – further adding to the problem.

If we stop our emissions today, we won’t go back to the past. This is not reason, however, to continue with unbridled emissions. We are adaptable creatures, with credible knowledge of our climate’s future and how we can frame that future. We’re already stuck with some amount of guaranteed climate change at this point. Rather than trying to recover the past, we need to be thinking about best possible futures.

The Conversation

Read more: http://www.iflscience.com/environment/what-would-happen-climate-if-we-stopped-emitting-greenhouse-gases-today