• Skip to primary navigation
  • Skip to main content
  • Skip to footer

Deforestation and the Future of the Amazon

Transcript of Part 1: Consequences of Amazon Deforestation

00:00:07.15	I'm Christopher Neill.
00:00:09.01	I'm a senior scientist at the Woods Hole Research Center
00:00:11.26	in Woods Hole, Massachusetts,
00:00:13.18	and I've been working on the Amazon
00:00:16.03	since the early 1990s.
00:00:18.02	The Amazon is the world's largest tropical rainforest.
00:00:20.20	It covers an enormous area
00:00:23.14	of nearly 8 million square kilometers
00:00:25.12	in northern South America.
00:00:27.13	That's about seven-eighths the size
00:00:29.25	of the entire lower 48 states in the US.
00:00:33.00	It's a globally important ecosystem.
00:00:36.01	It's also one that's changing extremely rapid today,
00:00:38.28	largely because of human activities.
00:00:41.05	In this talk, I'll try to explain
00:00:43.14	why the Amazon is valuable,
00:00:46.10	how it's changing,
00:00:47.25	what's driving those changes,
00:00:49.23	and where those changes will likely drive the Amazon
00:00:53.14	in the future.
00:00:55.19	The Amazon forest occupies nine countries.
00:00:58.18	It's an enormous,
00:01:00.24	but still largely intact, forested area,
00:01:03.27	but it's being changed by human activities,
00:01:07.07	largely driven by deforestation
00:01:10.17	and clearing for agriculture.
00:01:12.23	I want to start by talking about what's at stake in this forest
00:01:16.06	-- what do we lose when forest is converted to other uses?
00:01:19.27	And how might we use what we know about the Amazon
00:01:26.07	to guide management and conservation of Amazon forest
00:01:28.20	into the future.
00:01:30.21	The Amazon contains an enormous storehouse of biodiversity.
00:01:34.14	Just an as example, it has maybe 1300 species of birds,
00:01:38.21	1800 species of fish
00:01:41.02	-- about 40% of those fish probably are not yet described --
00:01:45.16	it has enormous tree diversity,
00:01:48.10	probably 12000 or more species of trees alone,
00:01:51.14	and there are more species in one hectare of Amazon forest
00:01:55.01	than there are in all of Europe.
00:01:57.04	And it has 3000 species of plants.
00:02:01.06	So, there's just a...
00:02:03.09	it's evolved under a very stable, moist climate,
00:02:07.18	warm climate regime for hundreds of thousands of years,
00:02:11.04	which has led to this enormous diversity.
00:02:13.15	It also contains globally important stores of carbon.
00:02:17.28	The atmosphere, today, on Earth,
00:02:20.03	contains about 850 billion metric tons of carbon.
00:02:24.13	Humans, by burning fossil fuels,
00:02:27.09	have contributed about 255 billion metric tonnes.
00:02:30.24	Tropic forests today, on Earth,
00:02:33.29	contain 270 billion tonnes of carbon
00:02:36.00	-- that's more than humans have put into the atmosphere to date.
00:02:39.08	We need to keep that carbon out of the atmosphere
00:02:42.03	to avoid even more dramatic climate changes on Earth,
00:02:45.21	and the Amazon forest, alone,
00:02:48.19	contains about a third of that tropical forest carbon,
00:02:51.10	maybe about 86 billion metric tonnes of carbon.
00:02:55.00	So, thinking about ways of conserving the forest,
00:02:57.23	keeping that carbon in trees and out of the atmosphere,
00:03:00.28	is extremely important.
00:03:03.16	The Amazon is such a large forest that it
00:03:08.03	also regulates the regional South American
00:03:11.17	and even global climate.
00:03:13.10	The Amazon river itself is
00:03:16.20	larger than the next six largest rivers of Earth combined.
00:03:19.18	It contains 20% of the Earth's fresh water.
00:03:22.17	And roughly 50% of the rain
00:03:25.18	that gets delivered onto the Amazon forest
00:03:28.02	is recycled water that has been transpired
00:03:30.27	through the very large cover of trees
00:03:36.05	in the Amazon rainforest.
00:03:38.02	The Amazon is also important because it
00:03:42.04	provides services for people
00:03:43.26	-- people live and use the Amazon.
00:03:45.19	There are at least 220 ethnic groups
00:03:48.17	that live in the Amazon.
00:03:50.16	There are 170 languages that are spoken in the Amazon.
00:03:54.22	And while these 220 groups are probably...
00:03:57.17	are way less than the probably
00:04:00.04	1000 or so groups that existed before European settlement,
00:04:03.15	they're extremely important, diverse,
00:04:06.08	and an absolutely important component of the Amazon forest.
00:04:09.15	And, like this young girl with a Pintado catfish on the screen,
00:04:14.09	these forests are used by people in a lot of ways,
00:04:18.03	for food and sustenance.
00:04:20.11	But today the Amazon is at a crossroads.
00:04:24.02	That crossroads is caused by the intersection of several forces.
00:04:29.23	The driving, overall force is deforestation,
00:04:32.27	the clearing of forest for agriculture.
00:04:35.22	That leads to fragmentation.
00:04:38.20	The Amazon basin has been wet and green for a very long time,
00:04:44.04	it has not evolved with fire,
00:04:46.11	but the intersection of deforestation and fragmentation
00:04:50.06	and climate
00:04:52.11	leads to increased incidence of fire in the Amazon,
00:04:54.08	and I want to talk about why that's happening
00:04:56.08	and its consequences.
00:04:58.09	And the Amazon has been a site of the expansion of agriculture.
00:05:01.03	It's one of the last remaining areas of the world
00:05:04.15	with adequate rainfall,
00:05:06.09	where agriculture can expand,
00:05:08.22	and agriculture has been expanding
00:05:10.18	and it will continue to expand,
00:05:13.04	and it's important to incorporate
00:05:15.16	our understanding of Amazon ecology
00:05:17.22	into the ways that agriculture might be expanded
00:05:21.22	in tropical regions in the future.
00:05:23.17	And last, the global climate is changing,
00:05:25.27	and that's going to influence the Amazon
00:05:28.20	and it's going to interact with all these other factors.
00:05:30.20	Alright, let's take a look at these.
00:05:32.19	The Amazon has had, historically,
00:05:35.23	from the 1980s through the early 2000s,
00:05:39.16	very high deforestation rates.
00:05:41.23	Now, I live in Massachusetts and I like to show this graph
00:05:45.21	because it shows that through the early 2000s
00:05:48.03	the rate of clearing in the Brazilian portion of the Amazon alone,
00:05:51.28	which is the vast majority of the area and the deforestation,
00:05:56.15	was something on the order of 20000 square kilometers a year.
00:05:59.27	The area of the state of Massachusetts is 22000, roughly, square kilometers.
00:06:04.24	So, we were losing, during this period, every single year,
00:06:07.28	a forest the size of Massachusetts.
00:06:11.14	Most of that clearing during that period was for pasture.
00:06:14.28	Pasturing was a way of people claiming land
00:06:18.21	and using it for agriculture
00:06:21.23	in a not very intensive way,
00:06:25.01	and raising beef over a lot of that area.
00:06:28.24	That was the primary use of forested...
00:06:32.02	cleared forest land through the early 2000s.
00:06:35.15	That's changing and I'll talk about that
00:06:38.11	when I talk about agricultural expansion.
00:06:40.08	Deforestation leads to fragmentation.
00:06:43.07	This picture, here,
00:06:45.25	is an image that shows clearing for agriculture
00:06:51.00	on one side of the screen
00:06:53.00	and a forested reserve on the other.
00:06:55.14	So, it makes two points.
00:06:57.10	One is that when you clear forest,
00:06:59.11	you create lots of edges and lots of patches.
00:07:01.19	those have important ecological consequences.
00:07:04.05	It also shows that when you
00:07:07.26	draw boundaries for protected areas,
00:07:09.29	that that's a very effective mechanism
00:07:12.10	for keeping forests standing.
00:07:14.26	What does fragmentation do?
00:07:16.22	It does a lot things,
00:07:19.01	but one of the most important is
00:07:21.24	it accelerates extinction in fragmented forest.
00:07:26.24	This is just a plot of the proportion of species
00:07:30.11	that go extinct versus the area of fragments.
00:07:34.00	It's from a marvelous study done over decades, now, in Manaus,
00:07:37.23	called the Biological Dynamics of Forest Fragments Projects,
00:07:41.05	and it shows clearly that extinction rates
00:07:45.00	are low in large fragments,
00:07:46.28	over to the right of this graph,
00:07:48.27	and high in small fragments.
00:07:50.22	So, you isolate 1 hectare of forest,
00:07:52.23	you lose a third or more
00:07:57.28	of the total number of species in that fragment
00:08:00.03	over several decades
00:08:04.14	of experimental study shown by this work.
00:08:07.16	So, the other new phenomenon in the Amazon,
00:08:11.28	from my perspective, is fire.
00:08:14.02	Amazon forest is moist for much of the year,
00:08:18.07	it's green for most of the year
00:08:20.19	-- or, all of the year over most of the forest, I should say --
00:08:26.27	and for that reason it's not very flammable.
00:08:28.22	Right?
00:08:30.03	Most of the Amazon forest,
00:08:32.05	aside from some very small edges near that Brazilian cerrado,
00:08:34.06	or savannah,
00:08:36.13	did not evolve with fire as part of its ecological history.
00:08:40.10	So, you have this enormous area of evergreen forest
00:08:43.20	that is very fire-resistant.
00:08:45.23	Now, why is that?
00:08:47.18	That's because tropical rainforests of the Amazon,
00:08:51.03	over much of the Amazon area,
00:08:53.14	have very deep roots.
00:08:55.02	The soils are very, very deep.
00:08:57.08	They store water over many meters,
00:08:59.24	10 or 20 meters of soil profile.
00:09:02.26	So, it was discovered by Dan Nepstad and his colleagues,
00:09:07.23	in the early 1990s,
00:09:09.24	that these roots penetrated to 3, 5, 8, 10,
00:09:13.21	even 15 meters.
00:09:15.16	They're allowing those trees to access water.
00:09:18.11	So, those trees can sustain
00:09:20.29	a green forest canopy
00:09:23.00	during extremely dry periods of the year,
00:09:26.10	and much of the Amazon is dry for many months
00:09:28.15	-- almost no rain -- but the forest stays green.
00:09:32.04	This graph just shows a plot of forest root profile
00:09:36.03	versus a managed pasture root profile.
00:09:39.03	When you replace the forest with the pasture,
00:09:41.13	you decrease the number of roots going down
00:09:43.25	and the pasture ecosystem turns brown in the dry season.
00:09:48.10	When it turns brown, it becomes flammable.
00:09:50.00	So, one of the things that happens,
00:09:52.21	and I'm going to walk you through
00:09:56.02	this slightly complex graph,
00:09:57.23	is that, in the dry season,
00:10:00.14	when you have pasture,
00:10:03.22	the leaf area and the brownness increases,
00:10:06.07	so the leaf area goes down.
00:10:07.28	So, if you look here and here,
00:10:10.23	this leaf area, actually, in pasture, declines, right?
00:10:13.18	And the forest leaf area actually stays very constant,
00:10:16.25	so the forest stays green and the pasture turns brown.
00:10:20.00	What that does is here...
00:10:22.22	whereas in the forest, here,
00:10:25.00	the window in which the ecosystem is dry enough to burn
00:10:28.29	is minuscule, right?
00:10:30.18	And the chance that there is an ignition source
00:10:33.05	coupled with when it's dry enough
00:10:35.12	almost never happens.
00:10:36.22	But that window is dramatically increased in pasture.
00:10:40.18	So, you've put, now, a very flammable ecosystem
00:10:43.22	right adjacent to a forest ecosystem
00:10:46.09	that never really burned much,
00:10:49.11	and what happens is that fires
00:10:53.04	that start in pastures, either intentionally or accidentally,
00:10:55.25	now sort of move into the forest.
00:10:58.20	They creep into the understory,
00:11:01.00	they don't do a lot of damage the first burn,
00:11:03.04	but they set the forest up for future change.
00:11:06.27	So, there's a lot of this fire, now, this black area.
00:11:09.18	In this paper by Mark Cochrane,
00:11:12.02	he clearly showed that there's a lot of fire
00:11:14.21	sort of creeping in from the edges of pasture,
00:11:16.19	a consequence of fragmentation.
00:11:20.22	Another new phenomenon
00:11:23.02	that dramatically expanded in the 2000s
00:11:26.12	was the dramatic expansion
00:11:33.06	of crop agriculture into the Amazon.
00:11:35.04	So, remember,
00:11:37.18	previous agriculture was largely cattle ranching
00:11:39.18	-- growing of grass,
00:11:42.09	raising of cattle at fairly low densities.
00:11:43.26	Now, today, there's been a
00:11:48.05	dramatic expansion of cropping in the Amazon.
00:11:50.02	Now, 30-40 years ago,
00:11:52.14	the conventional wisdom was,
00:11:55.29	well, you can't grow crops in the Amazon.
00:11:57.18	The soils are too acid,
00:12:00.09	the aluminum is toxic to the plants,
00:12:02.21	the phosphorus fertility is very, very low.
00:12:04.26	Well, those barriers can be overcome
00:12:08.12	with modern farming methods
00:12:10.11	-- fertilization, liming, pesticides to control tropical pests.
00:12:15.05	So, cropland has just expanded very dramatically in the Amazon
00:12:19.10	since the mid-2000s.
00:12:21.08	The principal crop has been soybeans,
00:12:23.09	but, more and more,
00:12:25.11	soybeans have been crown
00:12:29.05	together with a second crop of corn or cotton,
00:12:31.10	and this is moving...
00:12:33.07	has moved very rapidly into the Amazon
00:12:34.29	from the southern end of the Amazon,
00:12:37.03	where there's a seasonal dry season
00:12:39.00	that works to control pests and diseases
00:12:41.16	fairly effectively.
00:12:43.26	This has been a fruit of a green revolution
00:12:46.19	that's developed crop varieties
00:12:49.04	that can grow in hot tropical climates,
00:12:52.06	like the soybean varieties that can adapt to tropical day length
00:12:55.05	and the ability to use large amounts of fertilizer and pesticides.
00:12:58.07	Soybeans is interesting
00:13:01.22	because soybeans is now a global commodity,
00:13:04.02	so, where I work in the Amazon,
00:13:05.25	you see trucks like this lined up on dirt roads
00:13:08.22	more than 1000 miles from the port.
00:13:11.04	They get loaded with soybeans from the Amazon,
00:13:13.22	they travel on dirt roads,
00:13:15.21	and then reach paved roads,
00:13:17.14	and so there's this global transport network
00:13:19.23	that takes soybeans from the central Amazon,
00:13:22.25	you know... agricultural region,
00:13:26.13	all the way to other parts of the world.
00:13:28.12	And what's interesting is that, since roughly 2000,
00:13:32.24	exports to China, here,
00:13:34.28	this blue slab on this graph,
00:13:38.08	have increased dramatically,
00:13:40.23	and China now dominates the Amazon soybean export market.
00:13:45.07	So, we've moved from a world in which
00:13:49.00	soybeans were mostly grown outside the Amazon
00:13:50.28	to a point where Brazil is now
00:13:53.07	the world's largest soybean exporter,
00:13:55.02	and China has been a major destination
00:13:58.00	for Amazon soybeans in very recent years.
00:14:03.09	The other change that's occurring in the Amazon is climate.
00:14:06.21	This map shows, in red,
00:14:09.27	the areas where there are significant numbers of dry months.
00:14:12.20	So, if you look here,
00:14:14.26	in the southern Amazon region...
00:14:17.02	and this just shows the Brazil...
00:14:20.27	the place, here, where I'm pointing is
00:14:25.07	pretty much the area of very dramatic agricultural expansion,
00:14:28.01	there are 4-5 dry months.
00:14:31.10	What's important, now, is those dry months
00:14:33.25	are setting the Amazon up for
00:14:36.07	increased interactions between fire and drought and agriculture,
00:14:40.08	over very large areas.
00:14:42.06	I want to talk about drought,
00:14:44.12	because it's a very hot topic in the Amazon right now,
00:14:47.09	and it's important to understand
00:14:50.03	what the Amazon might look like
00:14:53.00	if droughts increase, and El Niño’s
00:14:55.19	-- strong El Niño’s, especially --
00:14:58.01	bring very dry conditions to the Amazon.
00:14:59.22	This is a picture of an experiment that was done
00:15:02.09	in the central Amazon, near the city of Santarém,
00:15:05.25	and it was called the Dry Forest,
00:15:09.11	or Seca Floresta, Experiment.
00:15:11.08	And this involved placing
00:15:16.08	about 7000 plastic panels in the forest understory
00:15:18.26	to exclude rain,
00:15:21.17	so, in this experiment, rain was excluded.
00:15:23.21	About 60% of the rainfall that fell
00:15:27.25	in the rainy season on this forest was intercepted
00:15:29.21	and moved away,
00:15:31.20	and they studied, over several years,
00:15:33.17	the responses of the trees.
00:15:35.10	And it was very interesting
00:15:37.11	and I'll just highlight one of the results.
00:15:39.10	Drought induced mortality of large trees,
00:15:41.27	and that mortality didn't start in the first year,
00:15:45.05	it wasn't dramatic in the second year,
00:15:48.05	but after three years of induced drought
00:15:51.26	there was a very dramatic increase in tree mortality.
00:15:56.06	And this, really, is an interesting thing,
00:16:01.07	because fire, when it moves through the understory,
00:16:03.06	tends to kill small trees.
00:16:04.24	Drought tends to kill the big trees
00:16:06.14	and it's the big trees that have all the carbon,
00:16:08.17	and it's the big trees
00:16:11.02	that provide the microclimate and other conditions
00:16:13.13	that sort of maintain the forest.
00:16:15.23	So, there's a very big
00:16:20.01	potential impact of increased drought
00:16:22.18	when they come, sort of, year after year after year.
00:16:24.29	The other effect of drought
00:16:27.20	is that it dramatically increases the potential for fire in the forest
00:16:31.28	and fragmented landscape.
00:16:33.18	So, here's a plot of years on the bottom
00:16:36.25	with the years, here,
00:16:39.27	of the water deficits, right?
00:16:43.29	So, you have... these are very dry years in these years, here,
00:16:50.22	where you've got this low water potential.
00:16:52.13	And in the same years where you have dry conditions,
00:16:54.15	this bar graph here is the area of Amazon that was burned.
00:16:58.07	So, when you have dry conditions,
00:17:00.26	like over here in 2010 or 2007,
00:17:03.18	you have a much larger area of Amazon forest that's burned,
00:17:08.25	in the larger Amazon forest region.
00:17:11.19	So, you set up that interaction:
00:17:14.15	drought plus fire means more forest degradation.
00:17:18.20	The worry is that this phenomenon,
00:17:22.11	this interaction,
00:17:24.18	may set up a tipping point where you actually
00:17:27.05	induce Amazon forest to become savannah.
00:17:29.08	You change the vegetation
00:17:31.01	and induce more grass,
00:17:32.19	which begets more fire,
00:17:34.21	and you actually change, over a significant fraction,
00:17:37.09	20-30% of the Amazon...
00:17:39.29	savannah-like conditions in a new global climate,
00:17:43.17	with longer dry seasons
00:17:46.21	and more potential occurrence of multi-year droughts.
00:17:50.03	So, what is the Amazon's future?
00:17:54.25	The good thing is the Amazon is still largely forest.
00:17:58.16	This is a map, again,
00:18:01.05	of the Amazon over nine countries,
00:18:03.27	and what you see in orange, at the bottom,
00:18:07.22	is agriculture expanding;
00:18:10.01	the purple is pasture, which has largely been focused
00:18:12.12	and occurring in the southern and eastern Amazon;
00:18:15.10	but large areas of the basin are still forested.
00:18:18.11	The dark green areas are forest reserves.
00:18:21.16	Those reserve areas have grown
00:18:24.26	and, in fact, Brazil has expanded
00:18:28.13	its protected area network
00:18:30.19	very significantly since the mid-2000s.
00:18:33.20	The other bright spot is that, since 2000,
00:18:38.01	deforestation rates in the Brazilian portion of the basin,
00:18:40.08	which is where the major deforestation was occurring,
00:18:42.27	have dropped dramatically since that period of high deforestation
00:18:47.24	that I talked about, through the early 2000s.
00:18:51.02	In fact, Brazil has gone from having deforestation rates of,
00:18:55.25	say, 20000 square kilometers a year
00:18:58.07	to down in the range of 5000 square kilometers,
00:19:01.08	where it's almost a 75% drop in deforestation.
00:19:05.02	And that occurred for a number of reasons.
00:19:07.08	One is better policing of illegal deforestation.
00:19:12.17	Another is expansion of protected areas.
00:19:16.11	Another region, which is very important
00:19:18.26	now that Brazil is selling soybeans and corn
00:19:22.03	into the international market,
00:19:24.11	is those markets demand
00:19:27.13	that those agricultural products
00:19:30.19	be produced in a more sustainable way.
00:19:34.23	And this was a protest in the central Amazon
00:19:37.04	carried out by Greenpeace,
00:19:39.14	that triggered a series of events
00:19:42.01	that led to a moratorium on the growing and selling of soybeans
00:19:45.14	into international markets,
00:19:47.12	from areas that were cleared after 2006.
00:19:51.20	And what this did is it forced agriculture
00:19:57.08	to occupy lands that were already cleared,
00:20:00.04	rather than the clearing of new land.
00:20:03.16	And I think, if we look forward to the future of the Amazon,
00:20:07.04	an absolutely major, important question
00:20:11.07	is how Brazil and other Amazon countries
00:20:17.17	manage agriculture in ways
00:20:19.29	that allow that agriculture to intensify,
00:20:22.04	to produce more on less land,
00:20:25.19	and act as a reducer of the need to clear new land,
00:20:29.29	to put new land into production.
00:20:32.20	And there's very good evidence that this is already happening.
00:20:35.24	Here's a plot of soy production and beef production,
00:20:40.20	and, remember, the deforestation started dropping in 2006.
00:20:44.24	What it showed is that reducing deforestation
00:20:49.19	doesn't have to lead to a decline in commodity production,
00:20:52.08	either soy or beef.
00:20:54.05	The yields of soy have remained fairly constant.
00:20:56.26	The yields of beef
00:20:59.01	-- that is, the ability to grow cattle, rather than at 1 head/hectare,
00:21:03.29	at 2 or more heads/hectare --
00:21:07.21	have allowed more beef to be produced on less land.
00:21:09.20	So, beef production, even in the face of falling deforestation,
00:21:12.26	has been sustained without...
00:21:16.06	the beef production has been sustained
00:21:20.19	on a smaller total area of pasture.
00:21:24.05	I think this is part of the way
00:21:27.22	we need to think about managing agriculture,
00:21:29.25	which is the driver of most of the deforestation in the Amazon going forward.
00:21:35.15	So, that's an overview of the drivers
00:21:38.22	and the ecological forces
00:21:42.19	interacting and shaping the future of the Amazon
00:21:44.16	-- very, very large questions remain.
00:21:46.07	One of the ones that I'm most interested in,
00:21:48.18	and that I'm actively working on,
00:21:51.00	is, how can agriculture intensify
00:21:54.09	without increasing environmental impacts to air and water?
00:21:57.01	And what are these impacts?
00:21:58.12	Well, they're greenhouse gas emissions from agricultural fields,
00:22:00.24	they're emissions of methane from cattle production,
00:22:03.11	they're emissions of nitrous oxide from agriculture
00:22:06.00	when you apply large amounts of fertilizers,
00:22:08.18	which is required for growing, especially two crops,
00:22:13.16	in the Amazon.
00:22:14.28	So, those questions are, how can that be managed?
00:22:17.07	How can we precisely use fertilizer
00:22:20.28	and manage agriculture to reduce impacts?
00:22:23.26	Will we end up,
00:22:26.10	if we're using lots of fertilizer,
00:22:28.15	in these now largely agricultural landscapes,
00:22:30.11	will those fertilizers move from land into streams?
00:22:33.26	And result in the degradation of water quality,
00:22:37.05	like we see in many regions,
00:22:40.25	say, the Mississippi Basin or south Florida
00:22:43.20	or the East Coast, Chesapeake Bay, of the United States?
00:22:45.23	That's a really big question,
00:22:47.22	and this intensification is just now beginning,
00:22:50.07	in the long-term time sense.
00:22:52.17	So, we need to understand that and that's a very big question.
00:22:55.21	The other big question that I think is even more and important
00:22:59.06	and, in some ways, harder and more challenging to address,
00:23:02.11	but we can make a lot of progress,
00:23:05.11	is how much forest can be cleared
00:23:07.15	before we reduce rainfall over the remaining forest,
00:23:13.12	and hence sustain this evergreen forest
00:23:16.01	and prevent forest degradation?
00:23:18.22	And sustain the intensive agriculture
00:23:21.22	that we're now depending on to be a bulwark
00:23:24.11	against the need to clear new forest land?
00:23:27.11	If 50% of the rain is coming from evaporated water...
00:23:30.20	you evaporate much less water from cropland than forest,
00:23:34.15	so you absolutely have to maintain
00:23:39.15	a certain amount of that forest to generate the rainfall
00:23:42.25	that you're now counting on to sustain the forest
00:23:45.12	that you're trying to protect,
00:23:47.22	and to produce agriculture and crops
00:23:50.21	in a more intensive way.
00:23:52.12	That's a big unknown,
00:23:55.00	I think that's an absolutely critical area of future research and a big unknown.
00:23:58.02	We think that that number is more than half of the Amazon forest
00:24:04.07	-- we're approaching 25% of the total Amazon forest cleared --
00:24:08.16	so we're reaching a point where we may see
00:24:12.17	these irreversible effects.
00:24:14.18	But I think that it's both the worry and the hope, right?
00:24:17.08	We have to intensify agriculture in the Amazon
00:24:20.01	to be able to have agricultural production,
00:24:23.19	it's... agricultural crops are Brazil's number one export, for example,
00:24:28.16	but we also need that forest to sustain this system
00:24:31.21	that we're counting on as a way of protecting the climate.
00:24:38.18	So, that's an introduction to the Amazon,
00:24:43.08	why it's important,
00:24:45.07	how it's changing,
00:24:47.12	and how it might change in the future.
00:24:49.07	There's progress, a lot of progress has been made on reducing deforestation
00:24:51.25	in the last decade.
00:24:53.20	It's still a challenge to reduce deforestation to zero.
00:24:56.03	Brazil has pledged to reduce deforestation to zero by 2030.
00:25:01.08	That remains a real challenge, but I think now...
00:25:04.19	I wouldn't have said this 15 years ago,
00:25:06.07	but it remains a real possibility.
00:25:10.12	I'd like to acknowledge my collaborators in this work
00:25:13.25	at the Marine Biological Lab
00:25:16.12	at the Woods Hole Research Center.
00:25:18.17	Also, our wonderful NGO collaborators
00:25:20.27	at the Institute for Amazon Environmental Research,
00:25:23.04	based in Brasilia.
00:25:25.05	The University of São Paulo, the University of Potsdam,
00:25:27.19	Max Planck Institute for Biogeochemistry,
00:25:30.04	Brown University,
00:25:32.11	and also to Grupo Amaggi for giving us permission
00:25:35.19	to work on a giant soybean farm in the state of Mato Grosso
00:25:38.17	in Brazil.
00:25:40.05	This work that I've talked about has been made possible
00:25:42.23	by a wide variety of funding sources,
00:25:44.25	including from NSF, NASA,
00:25:47.10	Gordon & Betty Moore Foundation,
00:25:49.16	the Research Foundation for the State of São Paulo,
00:25:51.26	and the Brazilian national science agency, CNPq.

This material is based upon work supported by the National Science Foundation and the National Institute of General Medical Sciences under Grant No. 2122350 and 1 R25 GM139147. Any opinion, finding, conclusion, or recommendation expressed in these videos are solely those of the speakers and do not necessarily represent the views of the Science Communication Lab/iBiology, the National Science Foundation, the National Institutes of Health, or other Science Communication Lab funders.

© 2023 - 2006 iBiology · All content under CC BY-NC-ND 3.0 license · Privacy Policy · Terms of Use · Usage Policy
 

Power by iBiology