Of these sources, livestock production is the largest, accounting for an estimated Even if this goal is met, many climate impacts, such as sea level rise, will likely still continue for centuries. Imagine a scenario in where societies have transitioned away from coal and natural gas to wind, solar, and other renewable energy sources. In this scenario, public policy and infrastructure investments have made walking, cycling, and public transit the most accessible and popular forms of transportation.
Air travel is used only as a last resort. The responsibility for eating lower on the food chain falls most heavily on countries like the U. Changing diets on an international scale will require more than just educating consumers — national policies will need to shift in ways that support more plant-centric diets. The following list of suggested resources is intended as a starting point for further exploration, and is not in any way comprehensive.
Summary for Policymakers.
Climate Change & Metaphors: A Primer
Climate Change , Mitigation of Climate Change. In: Climate Change Synthesis Report. Summary for policymakers. Climate Change Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Washington, D. Implications of climate change for agricultural productivity in the early twenty-first century. Schmidhuber J, Tubiello FN. Global food security under climate change.
Proc Natl Acad Sci. Increasing CO2 threatens human nutrition. Global Change Research Program. Hatcher J. July Tilman D, Clark M. Global diets link environmental sustainability and human health. Johns Hopkins Center for a Livable Future; Food-miles and the relative climate impacts of food choices in the United States. Uncertainties are not shown, but range from about 0. Based on data from NOAA. Figure 3b. Answer: The only way to know for sure whether the temperature rise is natural or due to human activity is to perform experiments in which we compare what would happen on Earth with natural factors alone to what would happen when humans are included in the equation.
Figure 4 shows actual temperature measurements in black. The blue curve shows model predictions based only on natural factors, while the red or brownish-red curve includes the human contribution to the greenhouse gas concentration. Note that both models the one based on natural factors only and the one that also includes the human contribution match the actual data reasonably well before about But for the past few decades, the models that include only natural factors fail quite miserably, while the models that include the human contribution continue to match the actual data.
Key point for Question 4 : Climate models will never be foolproof, but current models match past data quite well and offer strong evidence in support of the claim that human activity is the primary cause of recent global warming. When you couple this evidence with the rock-solid foundation of the global warming argument given above, it becomes difficult to imagine any other explanation for the observed warming. Figure 4.
Global Warming Primer – by Jeffrey Bennett
This graph compares observed temperature changes black with the predictions of climate models that include only natural factors blue and models that also include the human contribution red. Only the models that include the human contribution to the greenhouse gas concentration match observations well. Answer : First of all, these scientists are extremely few in number. In other words, even these skeptics concede that carbon dioxide warms planets and that human activity is raising the carbon dioxide level, and therefore that without a change in human emissions of carbon dioxide, significant global warming will eventually occur.
Their so-called skepticism comes from a belief that current climate models are overestimating the rate at which global warming will occur, and therefore that we have time before we need to take drastic or expensive action. But if that were the case, then we would not expect the models to work very well at reproducing actual climate data — and as you can see in Figure 4, they work very well indeed. So think about it this way: Imagine that you consulted doctors about a tumor, and 97 of them said you need surgery and treatment, while 3 said they agreed your tumor was potentially dangerous, but felt you could safely leave it alone.
What would you do? More specifically:. Figure 5.
See a Problem?
These maps contrast the extent of the year-round Greenland ice sheet, shown in white, in and The pink area indicates the region in which at least some surface melting occurred during the warm season. While this does not mean that the entire ice sheet is at imminent risk of melting into the sea, it does show that melting is occurring at a much greater rate than most scientists had expected, which means sea level may rise more than previous estimates suggested.
Key point for Question 6 : Although there are uncertainties in the short-term decades consequences of global warming, there is no doubt about the basic underlying science. If we keep pumping carbon dioxide and other greenhouse gases into the atmosphere, Earth will warm up significantly, with all the attending consequences listed above.
Question 7: OK, sounds bad. But is there really anything we can do about it? After all, even if we eliminated our own carbon dioxide emissions, the rest of the world — especially China and India — will keep emitting more. This is not impossible — in a pinch, we could already do it with a combination of sources such as nuclear and renewables, and with a little investment we could tap much greater sources such as solar energy from space, new biofuels, and perhaps even nuclear fusion.
The only missing ingredient is political will. After all, they want to survive too… For a hilarious commentary on this topic, watch this Colbert video.
- Reviewer Information.
- La communication nest pas un jeu: Les spin-doctors à la française (French Edition);
- In solitario (Italian Edition).
- The Twisted Patriot!
- Climate Change Primer.
Key point for Question 7 : There is no cause for despair. The only major obstacle to solving the problem of global warming is the fact that we currently pay artificially low prices for fossil fuels, a result of the fact that users pay only the production costs while we socialize the costs of their consequences across society.
Yes, our current energy policy is socialism! For those like me who believe strongly in market-based solutions, this implies that a substantial carbon tax might be all it would take to solve this problem and give us clean, cheap, and abundant energy for future generations. Call your representatives, and tell them the time has come for a carbon tax that accounts for the true costs of fossil fuels.
Bottom Line. So there you have it. My opinion is that the risks of waiting are too great, and that the skeptics argument is rather like having a doctor tell you not to worry about quitting smoking, since we may find a cure for lung cancer before you die from it. So imagine writing or actually write one! Then ask yourself: How will they feel about the decisions you made?
To Learn More. There are many great resources available to help you learn more. In addition, here are a few of my favorite web resources:. Every time a claim is refuted, it pops back up in a slightly different form. To recap: There is 1 no doubt that carbon dioxide warms planets, and 2 no doubt that we are adding carbon dioxide to the atmosphere at a rapid rate. How could you draw any other conclusion but to expect that our actions will cause global warming?
Then, arm yourself with the real facts, which will always undermine the skeptic claims. How do I know? Figure 6a. This graph shows global average temperature data since But a realistic look shows an ongoing warming trend. See an animated version of this graph and of a similar graph for sea ice here. Note: These are the same data shown in Figure 3, except starting from and shown as a line chart rather than a bar chart. Figure 6b. Each of the thousands of 3-dimensional grid cells can be represented by mathematical equations that describe the materials in it and the way energy moves through it.
- Duke University Press - Global Climate Change!
- Global Climate Change: A Primer;
- The Kettles and the Keeps: Ghosts at War (Marc Miller: ghost writer Book 3).
- Duke professor Orrin Pilkey takes on the deniers in Global Climate Change: A Primer - INDY Week.
- Global Climate Change: A Primer;
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The advanced equations are based on the fundamental laws of physics, fluid motion, and chemistry. Results from each grid cell are passed to neighboring cells, and the equations are solved again. Repeating the process through many time steps represents the passage of time. Image source: NOAA. Climate models are based on well-documented physical processes to simulate the transfer of energy and materials through the climate system. Climate models, also known as general circulation models or GCMs, use mathematical equations to characterize how energy and matter interact in different parts of the ocean, atmosphere, land.
The results of processes modeled in each cell are passed to neighboring cells to model the exchange of matter and energy over time. Grid cell size defines the resolution of the model: the smaller the size of the grid cells, the higher the level of detail in the model. More detailed models have more grid cells, so they need more computing power. Climate models also include the element of time, called a time step.
Time steps can be in minutes, hours, days, or years.