Understanding Global Warming
but in what state is up to us.
It’s normal for regional ‘weather’ (and regional sea surface temperatures) to be hard to forecast with precision, and change rapidly within a general range. But does the same apply to the holocene climate that threatens to heat up much faster than the prehistoric late paleocene, and with more sea level rise? What are the implications of accelerated warming in a mild interglacial world populated by billions of people, many still thinking their contributions are a meaningless drop in the (overflowing) bucket?
Climatic “signal” vs. “noise” (fluctuation from ocean & solar cycles): Just the beginning (Updated here)
Ocean heat content anomaly, to 2000 meters
There’s a distinct human fingerprint in the climate of the last several decades, despite the temporary offsetting effect of things like sulfate pollution and natural variability (such as cyclically greater ocean down-mixing, accompanied by the dominance of La Niña sea surface patterns over the past decade plus).
Science has moved beyond just strengthening the attribution case, to refining projections based on physical processes, paleoclimatology, and human activity. Including how extra heat might affect the natural cycles that influence regional climates. Uncertainty remains on a number of details, partly because there’s no exact prehistoric analog to our situation (a rapid, globally-distributed forcing coupled with a black carbon influence, and mixed with the short-term cooling effect of sulfates). The main conclusions, though, are solid, and the stakes are high for the most populous civilization to exist on Earth. But there is a disconnect between the mainstream scientific community and the controversy-driven media. That would include claims that global warming doesn’t affect weather (when over time it can’t help but do so), and of it “stopping” with every down-tick in surface temperature, vs. a statistically significant trend visible even on shorter timescales:
What the scientific community is saying, reflecting the consensus (i.e, the majority position among ‘actual published researchers’):
A strong, credible body of scientific evidence shows that climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems…
– National Academy of Sciences
The bottom line is that CO2 is absolutely, positively, and without question, the single most important greenhouse gas in the atmosphere. It acts very much like a control knob that determines the overall strength of the Earth?s greenhouse effect…
– Dr. Andrew Lacis, NASA climatologist
To slow the rate of climate change, we can decrease the amount of carbon dioxide that we release into the atmosphere.
– National Center for Atmospheric Research
There is no single threshold above which climate change is dangerous and below which it is safe. There is a spectrum of impacts. But some of the largest impacts are effectively irreversible and the thresholds for them are very near… In particular, the melting and breakdown of polar ice sheets seems to be in the vicinity of a couple of degrees warming. This expectation is based on current high rates of mass loss from the ice sheets compared to relative stability through the Holocene (the past 10,000 years) and on past ice sheet response in periods such as the Pliocene (a few million years ago) when the Earth was a couple of degrees warmer than preindustrial times (and sea level up to 25m higher)…
– Dr. James Risbey, CSIRO Australia
Recent observations confirm that, given high rates of observed emissions, the worst-case IPCC scenario trajectories (or even worse) are being realized. For many key parameters, the climate system is already moving beyond the patterns of natural variability within which our society and economy have developed and thrived. These parameters include global mean surface temperature, sea-level rise, ocean and ice sheet dynamics, ocean acidification, and extreme climatic events. There is a significant risk that many of the trends will accelerate, leading to an increasing risk of abrupt or irreversible climatic shifts.
– 2009 Copenhagen climate congress of 2,500 scientists
The Earth’s climate is now clearly out of balance and is warming. Many components of the climate system, including the temperatures of the atmosphere, land and ocean, the extent of sea ice and mountain glaciers, the sea level, the distribution of precipitation, and the length of seasons, are now changing at rates and in patterns that are not natural and are best explained by the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th century…
– American Geophysical Union
There is no doubt that Greenland ice loss has not just increased above past decades, but it has accelerated. The implication is that sea level rise estimates will again need to be revised upward.
– Dr. Jason Box, Glaciologist
It’s not the right question to ask if this storm or that storm is due to global warming, or is it natural variability. Nowadays, there’s always an element of both.
– Dr. Kevin Trenberth, NCAR
As humans burn enormous amounts of fossil fuel (containing carbon removed over eons from the prehistoric atmosphere), gigatons of carbon dioxide are accumulating beyond the uptake capacity of today’s natural “carbon sinks”. With this imbalance, atmospheric concentration has increased 41% since industrialization, rivaling the smaller and much slower oscillations of glacial cycles (in which CO2 concentration follows temperature, as a feedback), and reaching it’s highest in at least 800,000 years. Other studies (Pagani et al., Pearson & Palmer, Hönisch et al.) suggest millions of years. And although there’s some short-term fluctuation, the trend continues to accelerate. This has changed the infrared transparency of Earth’s atmosphere similarly to the way a drop of ink changes the visible transparency of water. So what’s wrong with this change, and how can we improve the odds of ecosystem integrity and human prosperity into the future? First, a crash course on the basics.
Carbon dioxide plays vital roles in climate and the biosphere, but there can be too much of a good thing. An accumulation semi-permanently amplifies the greenhouse effect that keeps Earth’s average temperature above zero, causing warming (2). Research overwhelmingly indicates this is the main factor in a climatically strong trend, with much of the extra heat accumulated and distributed by the oceans (their thermal inertia produces a lagged atmospheric response). This rise, subject to fluctuation from things like ocean cycles (in the exchange of heat between the depths and the surface) and sulfate “aerosol”, is extensive but not uniform, and proxy studies suggest it has already exceeded anything in at least 2,000 years.
Heat is the ultimate driver of the climate system. Effects on evaporation, all precipitation types, reflective ice cover, oceanic and atmospheric circulation, and storm behavior would make “global climate change” a more complete descriptor of the situation. Although it’s early in the process, and there are variables between climate change and disaster losses that have made direct attribution between them difficult, trends in heat waves and precipitation are already clear. And along with fast responses like increasing levels of water vapor (a reactive greenhouse gas), protracted warming is also subject to amplification by an interplay of longer-term feedbacks, like reduced carbon storage (example1, 2, and 3), and the release of more greenhouse gas from warming oceans, forests, peatlands, and tundras. Greater wildfire incidence and increased CO2 and methane emission from thawing permafrost (See sidebar) are examples. How fast carbon cycle effects will be is uncertain, but concerns have grown with an improved understanding of their lasting influence, and even the substantial mid-range climate projections have insufficiently assessed their potential.
Warming may not seem like an urgent problem in most temperate regions, where so far it has been largely subtle and mixed with significant variability. But it does have the potential to cause lasting disruption, since many things in today’s world are vulnerable to rapid change. The rate of warming (and carbonic ocean acidification) will be a key to how ecosystems and large human populations will be impacted. Many a scientist would say past climate change has helped shape humanity (usually in transitions over thousands or millions of years), but so has the relatively mild, stable holocene in which intensive agriculture and modern civilization have developed, allowing us to expand our horizons beyond the mere struggle for survival.
Nature is not without resilience, but with cumulative pressures, biomes can weaken and change can snowball. Yet we can limit it’s progression and protect the biologically-rich interglacial that has helped societies thrive. Markets are more globalized, so this will take international efforts to reduce emissions from sources like electric generation, animal agriculture, and transport (none of which are likely to realize sufficient cuts alone). As well as technology to handle changes already underway. And those in the middle and upper classes, who’ve benefited most from a fossil-fueled system, are the ones more likely to have the means to help foster newer technologies. Still, certain ideological forces seek to cast doubt on strong science, or downplay the negatives while emphasizing some regional benefit (from moderate warming). An industry of disinformation has arisen, similar to past efforts to deny the health effects of cigarettes, with some of the same players. And those PR operations have helped delay a stewardship-oriented approach.
Delay means locking in stronger impacts, including on agriculture and resource reliability. This issue is about the risk of rapid climate change and greater instability, and the many potential effects on today’s ecosystems and societies. If we stop ourselves from pushing too far, we at least have the chance at several thousand years of advancement; to become more resilient as a civilization, not just as a species.
from solar activity to the scientific consensus
Although preliminary research suggests a possible link with a warming Arctic, it’s still regional weather fluctuation (related to heat ‘distribution’ not just Earth’s “energy budget”)
A rundown of the latest on oceanic modulation of global surface warming (for some, a source of doubt and complacency)
“The heat content of the oceans is growing and growing. That means that the greenhouse effect has not taken a pause and the cold sun is not noticeably slowing global warming”.
(more on Antarctica’s unique climate and cryology)
West Antarctic Ice Sheet losing “considerably more than when last surveyed“.
Suggests “neither the rapid increase in temperature from the 1970s through the 1990s nor the slowdown of warming in the early 21st century appear to be significantly related to changes of Rs (solar radiation reaching the Earth’s surface)”
Which lifeforms will successfully adapt?
Study affirms meltwater impact on accelerated glacier flow
Earth is Still Warming: A LOT
What could be causing it?
IPCC, Assessing Climate Risks, Consistently Underestimates
Process is “inherently conservative“. And how it relates to the Arctic meltdown.
How the Arctic “death spiral” favors persistent, extreme weather patterns
Related: Dr. Jeff Masters discusses research on the Arctic influence.
Related: MIT Analysis suggests climate change odds much worse than thought
“without rapid and massive action”
Bad Science: Long-term CO2 rise natural/related to El Nino?
Paper ignores past findings, lacks logic and is biased by modest short-term fluctuations. It’s humlum again.
Drop In U.S. CO2 Emissions: Real “Weight” Loss, Or Just A Fad Diet?
As global emissions rise, U.S. emissions fall (with help from natural gas, a sluggish economy, and off-shored manufacturing). What about the longer-term CO2 & methane picture?
Biggest Jump Ever Seen in Global Warming Gases
Global emissions higher than the worst case projections.
Study: Ocean Less Able to Mitigate Climate Change
Capacity to take up the carbon humans put in the atmosphere is waning?
The Real Cost of Conventional Nuclear
Why there is no “renaissance”
More findings of anomalous warming
Complimentary to supposedly dead “hockey stick”
Second “100 year” Amazon drought in five years
“Current emissions pathways risk playing Russian roulette with the world’s largest rainforest” (and it’s carbon pool).
Support for the higher end of Climate sensitivity estimates
Two new studies on cloud feedback
Sub-Arctic wildfire intensity increasing
Another amplifying feedback
Extreme Events Linked to Global Warming?
The better way to think of it
Cap & trade
The conservative argument for not demonizing it
Subsea permafrost destabilizing as climate warms, future of greenhouse gas deposits uncertain
If it walks like a duck …
An allegory for climate “debate”.
George Will’s “cooling” Earth nonsense
More on this topic in #40 below
Natural ENSO responsible for warming trend?
“Atrocious” paper makes it into JGR
Climate change and famine: Will agriculture simply shift North?
Estimates of sea level rise refined
Study suggests an upper bound for this century, and a range greater than that of the IPCC. Some media outlets misinterpret.
How Do We Really Know?…
A brief look at the case for human influence
Direct tinkering with climate: Questions and caveats
Journalists misinterpret UK decision on “Inconvenient Truth”
Judge also made some errors in assessment
Western countries “outsource ” emissions to China
Total emissions rise from carbon-intensive manufacturing
How to make the trend look normal
Peer Review: A Necessary but Not Sufficient Condition
Weeding out bad science
G.W. Swindle ?
Scientists feel swindled by TV documentary
Record Temperature Anomaly for 2005
(this is with solar activity “declining slightly” and no El Niño influence on the global average)
Human activity-and very little else-is warming the world’s oceans (Complete Scripps report here)
A “dazzling debunking of climate change science”
Actually, another lesson in contrarian disinformation
Ocean acidification: “The Other Problem…”
Corals, CO2-absorbing phytoplankton affected